"The Shadow Thief" is a children's fantasy novel written by Annette Curtis Klause. The story follows a young boy named Zachary who discovers he has the ability to manipulate shadows. As he learns to control this power, he encounters various challenges and adventures that test his courage and creativity. Throughout the book, Zachary meets a mysterious character known as the Shadow Thief, who seeks to steal shadows for his own gain. The narrative explores themes of friendship, bravery, and the importance of embracing one's unique abilities while navigating the complexities of growing up.