diff --git a/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/controller/BookController.java b/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/controller/BookController.java
index 3b3636db..1f3e28f7 100644
--- a/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/controller/BookController.java
+++ b/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/controller/BookController.java
@@ -1,11 +1,14 @@
 package com.keploy.springbootpostgresgraphql.controller;
 
+import com.keploy.springbootpostgresgraphql.dto.AuthorInput;
+import com.keploy.springbootpostgresgraphql.dto.BookInput;
 import com.keploy.springbootpostgresgraphql.entity.Author;
 import com.keploy.springbootpostgresgraphql.entity.Book;
 import com.keploy.springbootpostgresgraphql.repository.AuthorRepository;
 import com.keploy.springbootpostgresgraphql.repository.BookRepository;
 import org.springframework.beans.factory.annotation.Autowired;
 import org.springframework.graphql.data.method.annotation.Argument;
+import org.springframework.graphql.data.method.annotation.MutationMapping;
 import org.springframework.graphql.data.method.annotation.QueryMapping;
 import org.springframework.stereotype.Controller;
 
@@ -24,6 +27,11 @@ public Book getBookByName(@Argument String name) {
         return bookRepository.findBookByName(name);
     }
 
+    @QueryMapping
+    public Book getBookById(@Argument int id) {
+        return bookRepository.findBookById(id);
+    }
+
     @QueryMapping
     public List<Book> getAllBooks() {
         return bookRepository.findAll();
@@ -39,5 +47,46 @@ public List<Author> getAllAuthors() {
         return authorRepository.findAll();
     }
 
+    @MutationMapping
+    public Book addBook(@Argument BookInput book) {
+        Author author = authorRepository.findAuthorById(book.getAuthorId());
+        Book newBook = new Book();
+        newBook.setName(book.getName());
+        newBook.setPageCount(book.getPageCount());
+        newBook.setAuthor(author);
+        return bookRepository.save(newBook);
+    }
+
+    @MutationMapping
+    public Book updateBook(@Argument int id, @Argument BookInput book) {
+        Book existingBook = bookRepository.findBookById(id);
+        if (existingBook != null) {
+            Author author = authorRepository.findAuthorById(book.getAuthorId());
+            existingBook.setName(book.getName());
+            existingBook.setPageCount(book.getPageCount());
+            existingBook.setAuthor(author);
+            return bookRepository.save(existingBook);
+        }
+        return null;
+    }
 
+    @MutationMapping
+    public Boolean deleteBook(@Argument int id) {
+        bookRepository.deleteById(id);
+        return true;
+    }
+
+    @MutationMapping
+    public Author addAuthor(@Argument AuthorInput author) {
+        Author newAuthor = new Author();
+        newAuthor.setFirstName(author.getFirstName());
+        newAuthor.setLastName(author.getLastName());
+        return authorRepository.save(newAuthor);
+    }
+
+    @MutationMapping
+    public Boolean deleteAuthor(@Argument int id) {
+        authorRepository.deleteById(id);
+        return true;
+    }
 }
diff --git a/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/dto/AuthorInput.java b/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/dto/AuthorInput.java
new file mode 100644
index 00000000..c2d5e66e
--- /dev/null
+++ b/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/dto/AuthorInput.java
@@ -0,0 +1,13 @@
+package com.keploy.springbootpostgresgraphql.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class AuthorInput {
+    private String firstName;
+    private String lastName;
+}
diff --git a/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/dto/BookInput.java b/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/dto/BookInput.java
new file mode 100644
index 00000000..0d237e53
--- /dev/null
+++ b/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/dto/BookInput.java
@@ -0,0 +1,14 @@
+package com.keploy.springbootpostgresgraphql.dto;
+
+import lombok.AllArgsConstructor;
+import lombok.Data;
+import lombok.NoArgsConstructor;
+
+@Data
+@AllArgsConstructor
+@NoArgsConstructor
+public class BookInput {
+    private String name;
+    private int pageCount;
+    private int authorId;
+}
diff --git a/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/repository/BookRepository.java b/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/repository/BookRepository.java
index ba4eedc0..d9003192 100644
--- a/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/repository/BookRepository.java
+++ b/spring-boot-postgres-graphql/src/main/java/com/keploy/springbootpostgresgraphql/repository/BookRepository.java
@@ -11,6 +11,8 @@ public interface BookRepository extends JpaRepository<Book, Integer> {
 
     Book findBookByName(String name);
 
+    Book findBookById(int id);
+
     List<Book> findAll();
 
 }
diff --git a/spring-boot-postgres-graphql/src/main/resources/graphql/schema.graphqls b/spring-boot-postgres-graphql/src/main/resources/graphql/schema.graphqls
index 5a5c47bc..a9ee1530 100644
--- a/spring-boot-postgres-graphql/src/main/resources/graphql/schema.graphqls
+++ b/spring-boot-postgres-graphql/src/main/resources/graphql/schema.graphqls
@@ -1,10 +1,30 @@
 type Query {
     getBookByName(name: String): Book
+    getBookById(id: ID!): Book
     getAllBooks: [Book]
     getAuthorById(id: Int): Author
     getAllAuthors: [Author]
 }
 
+type Mutation {
+    addBook(book: BookInput!): Book
+    updateBook(id: ID!, book: BookInput!): Book
+    deleteBook(id: ID!): Boolean
+    addAuthor(author: AuthorInput!): Author
+    deleteAuthor(id: ID!): Boolean
+}
+
+input BookInput {
+    name: String!
+    pageCount: Int!
+    authorId: Int!
+}
+
+input AuthorInput {
+    firstName: String!
+    lastName: String!
+}
+
 type Book {
     id: ID
     name: String