"The Boy Book" is a young adult novel written by E. Lockhart. It is the second book in the Ruby Oliver series, which follows the life of a high school girl navigating friendships, relationships, and the challenges of adolescence. The story is presented in a diary format, allowing readers to experience Ruby's thoughts and feelings directly. In "The Boy Book," Ruby explores her complicated relationships with boys and friends while dealing with the ups and downs of teenage life. The book addresses themes of love, heartbreak, and self-discovery, making it relatable for young readers facing similar experiences.