diff --git a/cqrs/src/main/java/com/iluwatar/cqrs/commandes/ICommandService.java b/cqrs/src/main/java/com/iluwatar/cqrs/commandes/ICommandService.java
new file mode 100644
index 000000000..4ccb0f456
--- /dev/null
+++ b/cqrs/src/main/java/com/iluwatar/cqrs/commandes/ICommandService.java
@@ -0,0 +1,19 @@
+package com.iluwatar.cqrs.commandes;
+
+public interface ICommandService {
+
+  public abstract void authorCreated(String username, String name, String email);
+
+  public abstract void bookAddedToAuthor(String title, double price, String username);
+
+  public abstract void authorNameUpdated(String username, String name);
+
+  public abstract void authorUsernameUpdated(String oldUsername, String newUsername);
+
+  public abstract void authorEmailUpdated(String username, String email);
+
+  public abstract void bookTitleUpdated(String oldTitle, String newTitle);
+
+  public abstract void bookPriceUpdated(String title, double price);
+
+}
diff --git a/cqrs/src/main/java/com/iluwatar/cqrs/queries/IQueryService.java b/cqrs/src/main/java/com/iluwatar/cqrs/queries/IQueryService.java
new file mode 100644
index 000000000..3cf4a2945
--- /dev/null
+++ b/cqrs/src/main/java/com/iluwatar/cqrs/queries/IQueryService.java
@@ -0,0 +1,20 @@
+package com.iluwatar.cqrs.queries;
+
+import java.util.List;
+
+import com.iluwatar.cqrs.dto.AuthorDTO;
+import com.iluwatar.cqrs.dto.BookDTO;
+
+public interface IQueryService {
+
+  public abstract AuthorDTO getAuthorByUsername(String username);
+
+  public abstract Double getBookPrice(String title);
+
+  public abstract List<BookDTO> getAuthorBooks(String username);
+
+  public abstract long getAuthorBooksCount(String username);
+
+  public abstract long getAuthorsCount();
+
+}