diff --git a/CaseAccounting/CaseAccounting.sln b/CaseAccounting/CaseAccounting.sln
index cc9910f..fee8363 100644
--- a/CaseAccounting/CaseAccounting.sln
+++ b/CaseAccounting/CaseAccounting.sln
@@ -5,9 +5,11 @@ VisualStudioVersion = 17.5.33424.131
 MinimumVisualStudioVersion = 10.0.40219.1
 Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CaseAccountingDataModels", "CaseAccountingDataModels\CaseAccountingDataModels.csproj", "{CAA81DB0-6CCA-4CBE-ABE2-94CDB190E05F}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CaseAccountingContracts", "CaseAccountingContracts\CaseAccountingContracts.csproj", "{5014C0D9-62EF-41AD-A8A1-22E89C43E062}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CaseAccountingContracts", "CaseAccountingContracts\CaseAccountingContracts.csproj", "{5014C0D9-62EF-41AD-A8A1-22E89C43E062}"
 EndProject
-Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CaseAccountingDataBaseImplement", "CaseAccountingDataBaseImplement\CaseAccountingDataBaseImplement.csproj", "{09C614AF-5BF5-4969-9609-D6A23DD74AA8}"
+Project("{9A19103F-16F7-4668-BE54-9A1E7A4F7556}") = "CaseAccountingDataBaseImplement", "CaseAccountingDataBaseImplement\CaseAccountingDataBaseImplement.csproj", "{09C614AF-5BF5-4969-9609-D6A23DD74AA8}"
+EndProject
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "CaseAccountingBusinessLogic", "CaseAccountingBusinessLogics\CaseAccountingBusinessLogic.csproj", "{4D95FDCC-80B3-452F-86FD-D514655ED0FB}"
 EndProject
 Global
 	GlobalSection(SolutionConfigurationPlatforms) = preSolution
@@ -27,6 +29,10 @@ Global
 		{09C614AF-5BF5-4969-9609-D6A23DD74AA8}.Debug|Any CPU.Build.0 = Debug|Any CPU
 		{09C614AF-5BF5-4969-9609-D6A23DD74AA8}.Release|Any CPU.ActiveCfg = Release|Any CPU
 		{09C614AF-5BF5-4969-9609-D6A23DD74AA8}.Release|Any CPU.Build.0 = Release|Any CPU
+		{4D95FDCC-80B3-452F-86FD-D514655ED0FB}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{4D95FDCC-80B3-452F-86FD-D514655ED0FB}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{4D95FDCC-80B3-452F-86FD-D514655ED0FB}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{4D95FDCC-80B3-452F-86FD-D514655ED0FB}.Release|Any CPU.Build.0 = Release|Any CPU
 	EndGlobalSection
 	GlobalSection(SolutionProperties) = preSolution
 		HideSolutionNode = FALSE
diff --git a/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/CaseLogic.cs b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/CaseLogic.cs
new file mode 100644
index 0000000..1b58584
--- /dev/null
+++ b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/CaseLogic.cs
@@ -0,0 +1,122 @@
+using CaseAccountingContracts.BindingModels;
+using CaseAccountingContracts.BusinessLogicContracts;
+using CaseAccountingContracts.SearchModels;
+using CaseAccountingContracts.StoragesContracts;
+using CaseAccountingContracts.ViewModels;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CaseAccountingBusinessLogic.BusinessLogics
+{
+    public class CaseLogic : ICaseLogic
+    {
+        private readonly ILogger _logger;
+        private readonly ICaseStorage _caseStorage;
+
+        public CaseLogic(ILogger<CaseLogic> logger, ICaseStorage caseStorage)
+        {
+            _logger = logger;
+            _caseStorage = caseStorage;
+        }
+
+        public bool Create(CaseBindingModel model)
+        {
+            CheckModel(model);
+            if (_caseStorage.Insert(model) == null)
+            {
+                _logger.LogWarning("Insert operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public bool Delete(CaseBindingModel model)
+        {
+            CheckModel(model, false);
+            _logger.LogInformation("Delete. Id:{Id}", model.Id);
+            if (_caseStorage.Delete(model) == null)
+            {
+                _logger.LogWarning("Delete operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public CaseViewModel? ReadElement(CaseSearchModel model)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            _logger.LogInformation("ReadElement. CaseName:{Name}.Id:{ Id}", model.Name, model.Id);
+            var element = _caseStorage.GetElement(model);
+            if (element == null)
+            {
+                _logger.LogWarning("ReadElement element not found");
+                return null;
+            }
+            _logger.LogInformation("ReadElement find. Id:{Id}", element.Id);
+            return element;
+        }
+
+        public List<CaseViewModel>? ReadList(CaseSearchModel? model)
+        {
+            _logger.LogInformation("ReadList. CaseName:{Name}.Id:{ Id}", model?.Name, model?.Id);
+            var list = model == null ? _caseStorage.GetFullList() : _caseStorage.GetFilteredList(model);
+            if (list == null)
+            {
+                _logger.LogWarning("ReadList return null list");
+                return null;
+            }
+            _logger.LogInformation("ReadList. Count:{Count}", list.Count);
+            return list;
+        }
+
+        public bool Update(CaseBindingModel model)
+        {
+            CheckModel(model);
+            if (_caseStorage.Update(model) == null)
+            {
+                _logger.LogWarning("Update operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        private void CheckModel(CaseBindingModel model, bool withParams = true)
+        {
+            if (model == null) 
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            if (!withParams)
+            {
+                return;
+            }
+            if (model.UserId < 0)
+            {
+                throw new ArgumentNullException("Некорректный идентификатор пользователя",
+                    nameof(model.UserId));
+            }
+            if (model.SpecializationId < 0)
+            {
+                throw new ArgumentNullException("Некорректный идентификатор специализации",
+                    nameof(model.SpecializationId));
+            }
+            if (model.Name == string.Empty)
+            {
+                throw new ArgumentNullException("Некорректное название дела",
+                    nameof(model.Name));
+            }
+            if(model.Date > DateTime.Now) 
+            {
+                throw new ArgumentNullException("Некорректное время заведения дела",
+                    nameof(model.Date));
+            }
+        }
+    }
+}
diff --git a/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/ContractLogic.cs b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/ContractLogic.cs
new file mode 100644
index 0000000..78c5e07
--- /dev/null
+++ b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/ContractLogic.cs
@@ -0,0 +1,117 @@
+using CaseAccountingContracts.BindingModels;
+using CaseAccountingContracts.BusinessLogicContracts;
+using CaseAccountingContracts.SearchModels;
+using CaseAccountingContracts.StoragesContracts;
+using CaseAccountingContracts.ViewModels;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CaseAccountingBusinessLogic.BusinessLogics
+{
+    public class ContractLogic : IContractLogic
+    {
+        private readonly ILogger _logger;
+        private readonly IContractStorage _contractStorage;
+
+        public ContractLogic(ILogger<ContractLogic> logger, IContractStorage contractStorage)
+        {
+            _logger = logger;
+            _contractStorage = contractStorage;
+        }
+
+        public bool Create(ContractBindingModel model)
+        {
+            CheckModel(model);
+            if (_contractStorage.Insert(model) == null)
+            {
+                _logger.LogWarning("Insert operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public bool Delete(ContractBindingModel model)
+        {
+            CheckModel(model, false);
+            _logger.LogInformation("Delete. Id:{Id}", model.Id);
+            if (_contractStorage.Delete(model) == null)
+            {
+                _logger.LogWarning("Delete operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public ContractViewModel? ReadElement(ContractSearchModel model)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            _logger.LogInformation("ReadElement. Id:{ Id}", model.Id);
+            var element = _contractStorage.GetElement(model);
+            if (element == null)
+            {
+                _logger.LogWarning("ReadElement element not found");
+                return null;
+            }
+            _logger.LogInformation("ReadElement find. Id:{Id}", element.Id);
+            return element;
+        }
+
+        public List<ContractViewModel>? ReadList(ContractSearchModel? model)
+        {
+            _logger.LogInformation("ReadList. Id:{ Id}", model?.Id);
+            var list = model == null ? _contractStorage.GetFullList() : _contractStorage.GetFilteredList(model);
+            if (list == null)
+            {
+                _logger.LogWarning("ReadList return null list");
+                return null;
+            }
+            _logger.LogInformation("ReadList. Count:{Count}", list.Count);
+            return list;
+        }
+
+        public bool Update(ContractBindingModel model)
+        {
+            CheckModel(model);
+            if (_contractStorage.Update(model) == null)
+            {
+                _logger.LogWarning("Update operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        private void CheckModel(ContractBindingModel model, bool withParams = true)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            if (!withParams)
+            {
+                return;
+            }
+            if (model.UserId < 0)
+            {
+                throw new ArgumentNullException("Некорректный идентификатор пользователя",
+                    nameof(model.UserId));
+            }
+            if (model.Coast <= 0) 
+            {
+                throw new ArgumentNullException("Некорректная стоимость услуги",
+                    nameof(model.Coast));
+            }
+            if (model.Service == string.Empty) 
+            {
+                throw new ArgumentNullException("Некорректное название услуги",
+                    nameof(model.Service));
+            }
+        }
+    }
+}
diff --git a/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/DealLogic.cs b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/DealLogic.cs
new file mode 100644
index 0000000..1ff3356
--- /dev/null
+++ b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/DealLogic.cs
@@ -0,0 +1,117 @@
+using CaseAccountingContracts.BindingModels;
+using CaseAccountingContracts.BusinessLogicContracts;
+using CaseAccountingContracts.SearchModels;
+using CaseAccountingContracts.StoragesContracts;
+using CaseAccountingContracts.ViewModels;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CaseAccountingBusinessLogic.BusinessLogics
+{
+    public class DealLogic : IDealLogic
+    {
+        private readonly ILogger _logger;
+        private readonly IDealStorage _dealStorage;
+
+        public DealLogic(ILogger<DealLogic> logger, IDealStorage dealStorage)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _dealStorage = dealStorage ?? throw new ArgumentNullException(nameof(dealStorage));
+        }
+
+        public bool Create(DealBindingModel model)
+        {
+            CheckModel(model);
+            if (_dealStorage.Insert(model) == null)
+            {
+                _logger.LogWarning("Insert operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public bool Delete(DealBindingModel model)
+        {
+            CheckModel(model, false);
+            _logger.LogInformation("Delete. Id:{Id}", model.Id);
+            if (_dealStorage.Delete(model) == null)
+            {
+                _logger.LogWarning("Delete operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public DealViewModel? ReadElement(DealSearchModel model)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            _logger.LogInformation("ReadElement. Id:{ Id}", model.Id);
+            var element = _dealStorage.GetElement(model);
+            if (element == null)
+            {
+                _logger.LogWarning("ReadElement element not found");
+                return null;
+            }
+            _logger.LogInformation("ReadElement find. Id:{Id}", element.Id);
+            return element;
+        }
+
+        public List<DealViewModel>? ReadList(DealSearchModel? model)
+        {
+            _logger.LogInformation("ReadList. Id:{ Id}", model?.Id);
+            var list = model == null ? _dealStorage.GetFullList() : _dealStorage.GetFilteredList(model);
+            if (list == null)
+            {
+                _logger.LogWarning("ReadList return null list");
+                return null;
+            }
+            _logger.LogInformation("ReadList. Count:{Count}", list.Count);
+            return list;
+        }
+
+        public bool Update(DealBindingModel model)
+        {
+            CheckModel(model);
+            if (_dealStorage.Update(model) == null)
+            {
+                _logger.LogWarning("Update operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        private void CheckModel(DealBindingModel model, bool withParams = true)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            if (!withParams)
+            {
+                return;
+            }
+            if (model.UserId < 0)
+            {
+                throw new ArgumentNullException("Некорректный идентификатор пользователя",
+                    nameof(model.UserId));
+            }
+            if (model.Subject == string.Empty) 
+            {
+                throw new ArgumentNullException("Некорректный предмет договора",
+                    nameof(model.Subject));
+            }
+            if (model.Responsibilities == string.Empty) 
+            {
+                throw new ArgumentNullException("Некорректно указаны обязанности договора",
+                    nameof(model.Responsibilities));
+            }
+        }
+    }
+}
diff --git a/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/HearingLogic.cs b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/HearingLogic.cs
new file mode 100644
index 0000000..017ee62
--- /dev/null
+++ b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/HearingLogic.cs
@@ -0,0 +1,117 @@
+using CaseAccountingContracts.BindingModels;
+using CaseAccountingContracts.BusinessLogicContracts;
+using CaseAccountingContracts.SearchModels;
+using CaseAccountingContracts.StoragesContracts;
+using CaseAccountingContracts.ViewModels;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CaseAccountingBusinessLogic.BusinessLogics
+{
+    public class HearingLogic : IHearingLogic
+    {
+        private readonly ILogger _logger;
+        private readonly IHearingStorage _hearingStorage;
+
+        public HearingLogic(ILogger<HearingLogic> logger, IHearingStorage hearingStorage)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _hearingStorage = hearingStorage ?? throw new ArgumentNullException(nameof(hearingStorage));
+        }
+
+        public bool Create(HearingBindingModel model)
+        {
+            CheckModel(model);
+            if (_hearingStorage.Insert(model) == null)
+            {
+                _logger.LogWarning("Insert operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public bool Delete(HearingBindingModel model)
+        {
+            CheckModel(model, false);
+            _logger.LogInformation("Delete. Id:{Id}", model.Id);
+            if (_hearingStorage.Delete(model) == null)
+            {
+                _logger.LogWarning("Delete operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public HearingViewModel? ReadElement(HearingSearchModel model)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            _logger.LogInformation("ReadElement. Id:{ Id}", model.Id);
+            var element = _hearingStorage.GetElement(model);
+            if (element == null)
+            {
+                _logger.LogWarning("ReadElement element not found");
+                return null;
+            }
+            _logger.LogInformation("ReadElement find. Id:{Id}", element.Id);
+            return element;
+        }
+
+        public List<HearingViewModel>? ReadList(HearingSearchModel? model)
+        {
+            _logger.LogInformation("ReadList. Id:{ Id}", model?.Id);
+            var list = model == null ? _hearingStorage.GetFullList() : _hearingStorage.GetFilteredList(model);
+            if (list == null)
+            {
+                _logger.LogWarning("ReadList return null list");
+                return null;
+            }
+            _logger.LogInformation("ReadList. Count:{Count}", list.Count);
+            return list;
+        }
+
+        public bool Update(HearingBindingModel model)
+        {
+            CheckModel(model);
+            if (_hearingStorage.Update(model) == null)
+            {
+                _logger.LogWarning("Update operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        private void CheckModel(HearingBindingModel model, bool withParams = true)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            if (!withParams)
+            {
+                return;
+            }
+            if (model.UserId < 0)
+            {
+                throw new ArgumentNullException("Некорректный идентификатор пользователя",
+                    nameof(model.UserId));
+            }
+            if (model.CaseId < 0)
+            {
+                throw new ArgumentNullException("Некорректный идентификатор дела",
+                    nameof(model.CaseId));
+            }
+            if (model.Information == string.Empty) 
+            {
+                throw new ArgumentNullException("Некорректна написана информация по делу",
+                    nameof(model.Information));
+            }
+        }
+    }
+}
diff --git a/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/LawyerLogic.cs b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/LawyerLogic.cs
new file mode 100644
index 0000000..faf7809
--- /dev/null
+++ b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/LawyerLogic.cs
@@ -0,0 +1,127 @@
+using CaseAccountingContracts.BindingModels;
+using CaseAccountingContracts.BusinessLogicContracts;
+using CaseAccountingContracts.SearchModels;
+using CaseAccountingContracts.StoragesContracts;
+using CaseAccountingContracts.ViewModels;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CaseAccountingBusinessLogic.BusinessLogics
+{
+    public class LawyerLogic : ILawyerLogic
+    {
+        private readonly ILogger _logger;
+        private readonly ILawyerStorage _lawyerStorage;
+
+        public LawyerLogic(ILogger<LawyerLogic> logger, ILawyerStorage lawyerStorage)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _lawyerStorage = lawyerStorage ?? throw new ArgumentNullException(nameof(lawyerStorage));
+        }
+
+        public bool Create(LawyerBindingModel model)
+        {
+            CheckModel(model);
+            if (_lawyerStorage.Insert(model) == null)
+            {
+                _logger.LogWarning("Insert operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public bool Delete(LawyerBindingModel model)
+        {
+            CheckModel(model, false);
+            _logger.LogInformation("Delete. Id:{Id}", model.Id);
+            if (_lawyerStorage.Delete(model) == null)
+            {
+                _logger.LogWarning("Delete operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public LawyerViewModel? ReadElement(LawyerSearchModel model)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            _logger.LogInformation("ReadElement. Id:{ Id}", model.Id);
+            var element = _lawyerStorage.GetElement(model);
+            if (element == null)
+            {
+                _logger.LogWarning("ReadElement element not found");
+                return null;
+            }
+            _logger.LogInformation("ReadElement find. Id:{Id}", element.Id);
+            return element;
+        }
+
+        public List<LawyerViewModel>? ReadList(LawyerSearchModel? model)
+        {
+            _logger.LogInformation("ReadList. Id:{ Id}", model?.Id);
+            var list = model == null ? _lawyerStorage.GetFullList() : _lawyerStorage.GetFilteredList(model);
+            if (list == null)
+            {
+                _logger.LogWarning("ReadList return null list");
+                return null;
+            }
+            _logger.LogInformation("ReadList. Count:{Count}", list.Count);
+            return list;
+        }
+
+        public bool Update(LawyerBindingModel model)
+        {
+            CheckModel(model);
+            if (_lawyerStorage.Update(model) == null)
+            {
+                _logger.LogWarning("Update operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        private void CheckModel(LawyerBindingModel model, bool withParams = true)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            if (!withParams)
+            {
+                return;
+            }
+            if (model.UserId < 0)
+            {
+                throw new ArgumentNullException("Некорректный идентификатор пользователя",
+                    nameof(model.UserId));
+            }
+            if (model.SpecializationId < 0) 
+            {
+                throw new ArgumentNullException("Некорректный идентификатор специализации",
+                    nameof(model.SpecializationId));
+            }
+            if (model.Experience < 0)
+            {
+                throw new ArgumentNullException("Некорректно указан опыт работы",
+                    nameof(model.Experience));
+            }
+            if (model.Name == string.Empty) 
+            {
+                throw new ArgumentNullException("Некорректное имя юриста",
+                    nameof(model.Name));
+            }
+            if (model.Surname == string.Empty)
+            {
+                throw new ArgumentNullException("Некорректная фамилия юриста",
+                    nameof(model.Surname));
+            }
+        }
+    }
+}
diff --git a/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/SpecializationLogic.cs b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/SpecializationLogic.cs
new file mode 100644
index 0000000..8f9121e
--- /dev/null
+++ b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/SpecializationLogic.cs
@@ -0,0 +1,112 @@
+using CaseAccountingContracts.BindingModels;
+using CaseAccountingContracts.BusinessLogicContracts;
+using CaseAccountingContracts.SearchModels;
+using CaseAccountingContracts.StoragesContracts;
+using CaseAccountingContracts.ViewModels;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CaseAccountingBusinessLogic.BusinessLogics
+{
+    public class SpecializationLogic : ISpecializationLogic
+    {
+        private readonly ILogger _logger;
+        private readonly ISpecializationStorage _specializationStorage;
+
+        public SpecializationLogic(ILogger<SpecializationLogic> logger, ISpecializationStorage specializationStorage)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _specializationStorage = specializationStorage ?? throw new ArgumentNullException(nameof(specializationStorage));
+        }
+
+        public bool Create(SpecializationBindingModel model)
+        {
+            CheckModel(model);
+            if (_specializationStorage.Insert(model) == null)
+            {
+                _logger.LogWarning("Insert operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public bool Delete(SpecializationBindingModel model)
+        {
+            CheckModel(model, false);
+            _logger.LogInformation("Delete. Id:{Id}", model.Id);
+            if (_specializationStorage.Delete(model) == null)
+            {
+                _logger.LogWarning("Delete operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public SpecializationViewModel? ReadElement(SpecializationSearchModel model)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            _logger.LogInformation("ReadElement. Id:{ Id}", model.Id);
+            var element = _specializationStorage.GetElement(model);
+            if (element == null)
+            {
+                _logger.LogWarning("ReadElement element not found");
+                return null;
+            }
+            _logger.LogInformation("ReadElement find. Id:{Id}", element.Id);
+            return element;
+        }
+
+        public List<SpecializationViewModel>? ReadList(SpecializationSearchModel? model)
+        {
+            _logger.LogInformation("ReadList. Id:{ Id}", model?.Id);
+            var list = model == null ? _specializationStorage.GetFullList() : _specializationStorage.GetFilteredList(model);
+            if (list == null)
+            {
+                _logger.LogWarning("ReadList return null list");
+                return null;
+            }
+            _logger.LogInformation("ReadList. Count:{Count}", list.Count);
+            return list;
+        }
+
+        public bool Update(SpecializationBindingModel model)
+        {
+            CheckModel(model);
+            if (_specializationStorage.Update(model) == null)
+            {
+                _logger.LogWarning("Update operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        private void CheckModel(SpecializationBindingModel model, bool withParams = true)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            if (!withParams)
+            {
+                return;
+            }
+            if (model.UserId < 0)
+            {
+                throw new ArgumentNullException("Некорректный идентификатор пользователя",
+                    nameof(model.UserId));
+            }
+            if (model.Name == string.Empty) 
+            {
+                throw new ArgumentNullException("Некорректное название специализации",
+                    nameof(model.Name));
+            }
+        }
+    }
+}
diff --git a/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/UserLogic.cs b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/UserLogic.cs
new file mode 100644
index 0000000..0159efc
--- /dev/null
+++ b/CaseAccounting/CaseAccountingBusinessLogics/BusinessLogics/UserLogic.cs
@@ -0,0 +1,117 @@
+using CaseAccountingContracts.BindingModels;
+using CaseAccountingContracts.BusinessLogicContracts;
+using CaseAccountingContracts.SearchModels;
+using CaseAccountingContracts.StoragesContracts;
+using CaseAccountingContracts.ViewModels;
+using Microsoft.Extensions.Logging;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace CaseAccountingBusinessLogic.BusinessLogics
+{
+    public class UserLogic : IUserLogic
+    {
+        private readonly ILogger _logger;
+        private readonly IUserStorage _userStorage;
+
+        public UserLogic(ILogger logger, IUserStorage userStorage)
+        {
+            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
+            _userStorage = userStorage ?? throw new ArgumentNullException(nameof(userStorage));
+        }
+
+        public bool Create(UserBindingModel model)
+        {
+            CheckModel(model);
+            if (_userStorage.Insert(model) == null)
+            {
+                _logger.LogWarning("Insert operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public bool Delete(UserBindingModel model)
+        {
+            CheckModel(model, false);
+            _logger.LogInformation("Delete. Id:{Id}", model.Id);
+            if (_userStorage.Delete(model) == null)
+            {
+                _logger.LogWarning("Delete operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public UserViewModel? ReadElement(UserSearchModel model)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            _logger.LogInformation("ReadElement. Id:{ Id}", model.Id);
+            var element = _userStorage.GetElement(model);
+            if (element == null)
+            {
+                _logger.LogWarning("ReadElement element not found");
+                return null;
+            }
+            _logger.LogInformation("ReadElement find. Id:{Id}", element.Id);
+            return element;
+        }
+
+        public List<UserViewModel>? ReadList(UserSearchModel? model)
+        {
+            _logger.LogInformation("ReadList. Id:{ Id}", model?.Id);
+            var list = model == null ? _userStorage.GetFullList() : _userStorage.GetFilteredList(model);
+            if (list == null)
+            {
+                _logger.LogWarning("ReadList return null list");
+                return null;
+            }
+            _logger.LogInformation("ReadList. Count:{Count}", list.Count);
+            return list;
+        }
+
+        public bool Update(UserBindingModel model)
+        {
+            CheckModel(model);
+            if (_userStorage.Update(model) == null)
+            {
+                _logger.LogWarning("Update operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        private void CheckModel(UserBindingModel model, bool withParams = true)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            if (!withParams)
+            {
+                return;
+            }
+            if (model.RoleId < 0)
+            {
+                throw new ArgumentNullException("Некорректный идентификатор роли",
+                    nameof(model.RoleId));
+            }
+            if (model.Login == string.Empty) 
+            {
+                throw new ArgumentNullException("Некорректный ввод логина",
+                    nameof(model.Login));
+            }
+            if (model.Password == string.Empty)
+            {
+                throw new ArgumentNullException("Некорректный ввод пароля",
+                    nameof(model.Password));
+            }
+        }
+    }
+}
diff --git a/CaseAccounting/CaseAccountingBusinessLogics/CaseAccountingBusinessLogic.csproj b/CaseAccounting/CaseAccountingBusinessLogics/CaseAccountingBusinessLogic.csproj
new file mode 100644
index 0000000..8e556ce
--- /dev/null
+++ b/CaseAccounting/CaseAccountingBusinessLogics/CaseAccountingBusinessLogic.csproj
@@ -0,0 +1,18 @@
+<Project Sdk="Microsoft.NET.Sdk">
+
+  <PropertyGroup>
+    <TargetFramework>net6.0</TargetFramework>
+    <ImplicitUsings>enable</ImplicitUsings>
+    <Nullable>enable</Nullable>
+  </PropertyGroup>
+
+  <ItemGroup>
+    <PackageReference Include="Microsoft.Extensions.Logging.Abstractions" Version="7.0.0" />
+  </ItemGroup>
+
+  <ItemGroup>
+    <ProjectReference Include="..\CaseAccountingContracts\CaseAccountingContracts.csproj" />
+    <ProjectReference Include="..\CaseAccountingDataModels\CaseAccountingDataModels.csproj" />
+  </ItemGroup>
+
+</Project>
diff --git a/CaseAccounting/CaseAccountingContracts/SearchModels/CaseSearchModel.cs b/CaseAccounting/CaseAccountingContracts/SearchModels/CaseSearchModel.cs
index 2f22a7b..01ec57e 100644
--- a/CaseAccounting/CaseAccountingContracts/SearchModels/CaseSearchModel.cs
+++ b/CaseAccounting/CaseAccountingContracts/SearchModels/CaseSearchModel.cs
@@ -17,5 +17,7 @@ namespace CaseAccountingContracts.SearchModels
         public string? Defendant { get; set; }
 
         public DateTime? Date { get; set; }
+
+        public int? UserId { get; set; }
     }
 }