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 blend of Greek mythology, humor, and adventure, The Lightning Thief is a thrilling read for fans of fantasy.