diff --git a/SushiBarBusinessLogic/ClientLogic.cs b/SushiBarBusinessLogic/ClientLogic.cs
new file mode 100644
index 0000000..4e68d36
--- /dev/null
+++ b/SushiBarBusinessLogic/ClientLogic.cs
@@ -0,0 +1,116 @@
+using Microsoft.Extensions.Logging;
+using SushiBarContracts.BindingModel;
+using SushiBarContracts.BusinessLogicsContracts;
+using SushiBarContracts.SearchModel;
+using SushiBarContracts.StoragesContracts;
+using SushiBarContracts.ViewModels;
+
+namespace SushiBarBusinessLogic
+{
+    public class ClientLogic : IClientLogic
+    {
+        private readonly ILogger _logger;
+        private readonly IClientStorage _clientStorage;
+        public ClientLogic(ILogger<ClientLogic> logger, IClientStorage clientStorage)
+        {
+            _logger = logger;
+            _clientStorage = clientStorage;
+        }
+        public bool Create(ClientBindingModel model)
+        {
+            CheckUser(model);
+            if (_clientStorage.Insert(model) == null)
+            {
+                _logger.LogWarning("Insert operation failed");
+                return false;
+            }
+            return true;
+        }
+        public bool Update(ClientBindingModel model)
+        {
+            CheckUser(model);
+            if (_clientStorage.Update(model) == null)
+            {
+                _logger.LogWarning("Update operation failed");
+                return false;
+            }
+            return true;
+        }
+        public bool Delete(ClientBindingModel model)
+        {
+            CheckUser(model, false);
+            _logger.LogInformation("Delete. Id:{Id}", model.Id);
+            if (_clientStorage.Delete(model) == null)
+            {
+                _logger.LogWarning("Delete operation failed");
+                return false;
+            }
+            return true;
+        }
+
+        public ClientViewModel? ReadElement(ClientSearchModel model)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            _logger.LogInformation("ReadElement. UserName:{UserName}.Id:{Id}", model.Email, model.Id);
+            var element = _clientStorage.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<ClientViewModel>? ReadList(ClientSearchModel? model)
+        {
+            _logger.LogInformation("ReadList. Email:{Email}.Id:{ Id} ", model?.Email, model?.Id);
+            var list = (model == null) ? _clientStorage.GetFullList() : _clientStorage.GetFilteredList(model);
+            if (list == null)
+            {
+                _logger.LogWarning("ReadList return null list");
+                return null;
+            }
+            _logger.LogInformation("ReadList. Count:{Count}", list.Count);
+            return list;
+        }
+
+        public void CheckUser(ClientBindingModel model, bool withParams = true)
+        {
+            if (model == null)
+            {
+                throw new ArgumentNullException(nameof(model));
+            }
+            if (!withParams)
+            {
+                return;
+            }
+            if (string.IsNullOrEmpty(model.ClientFIO))
+            {
+                throw new ArgumentNullException("Invalid fullname of user", nameof(model.ClientFIO));
+            }
+            if (string.IsNullOrEmpty(model.Email))
+            {
+                throw new ArgumentNullException("Invalid email of user", nameof(model.Email));
+            }
+            if (string.IsNullOrEmpty(model.Password))
+            {
+                throw new ArgumentNullException("Invalid password of user", nameof(model.Password));
+            }
+            _logger.LogInformation("Client. ClientFIO:{ClientFIO}. Email:{Email}. Id:{Id} ", model.ClientFIO, model.Email, model.Id);
+
+            var element = _clientStorage.GetElement(new ClientSearchModel
+            {
+                Email = model.Email
+            });
+
+            if (element != null && element.Id != model.Id)
+            {
+                throw new InvalidOperationException("User with such email already exists.");
+            }
+        }
+    }
+}
diff --git a/SushiBarDataModels/Interface1.cs b/SushiBarDataModels/IClientModel.cs
similarity index 100%
rename from SushiBarDataModels/Interface1.cs
rename to SushiBarDataModels/IClientModel.cs
diff --git a/SushiBarDataModels/IOrderModel.cs b/SushiBarDataModels/IOrderModel.cs
index 4e2c03d..a4098ea 100644
--- a/SushiBarDataModels/IOrderModel.cs
+++ b/SushiBarDataModels/IOrderModel.cs
@@ -5,6 +5,7 @@ namespace SushiBarDataModels
     public interface IOrderModel : IId
     {
         int SushiId { get; }
+        int ClientId { get; }
         int Count { get; }
         double Sum { get; }
         OrderStatus Status { get; }