The Lightning Thief is the first book in Rick Riordan's Percy Jackson & The Olympians series. It follows Percy Jackson, a twelve-year-old boy who discovers he is a demigod, the son of Poseidon. As Percy embarks on a quest to prevent a war among the gods, he encounters mythical creatures and learns about his own powers. With its witty humor, engaging storytelling, and introduction to Greek mythology, The Lightning Thief became a beloved YA classic.