"Double Act" is a children's novel written by Jacqueline Wilson. It tells the story of two identical twin sisters, Ruby and Garnet, who have very different personalities. Ruby is outgoing and adventurous, while Garnet is more reserved and cautious. The twins navigate the challenges of growing up, including their relationships with friends and family. As the story unfolds, the sisters face the ups and downs of their bond, learning important lessons about individuality and the importance of supporting one another. The book explores themes of identity, friendship, and the complexities of sibling relationships, making it relatable for young readers.