Dinosaurs Before Dark by Mary Pope Osborne

Jack and Annie discover a mysterious tree house filled with magical books. When they open a book about dinosaurs, they are whisked back to the Cretaceous Period. Armed with only a Pennsylvania guidebook and their wits, they must survive encounters with Triceratops, Stegosaurus, and the fearsome Tyrannosaurus Rex before finding their way home.

Perfect for young readers aged 6–9, this first book in the Magic Tree House series combines adventure, history, and wonder. Join millions of children worldwide who have fallen in love with Jack and Annie's time-traveling escapades and discovered that the best adventures are just a book away.