Through his wildly popular series Percy Jackson and the Olympians, Kane Chronicles, 39 Clues, and The Heroes of Olympus, Rick Riordan has sparked young readers' interest in world mythology and literature, a renewed fascination that is reinforced by film adaptations, toys, games, and other tie-ins. As a child, Riordan thought of books as too difficult to read and, in the end, not very interesting or worth the effort-in fact, he grew up as a reluctant...