New author Judson Troop's debut novel, The Gatekeeper: Day of the Dinosaurs, is a fascinating giant of a tale for young readers. And by "giant," the author means to submerge young readers into a world of dinosaurs, Native American legends, time travel, and prehistory. Eleven-year-old Rickey Ellis has more to worry about than classroom bullies and school rivals. While he's on a fieldtrip to a curious museum built over a quarry filled with fossilized dinosaurs in northwest Colorado, he accidently unlocks a time portal. Once a closely guarded secret by a now long-vanished tribe known as the Makori, there might be something to an ancient Indian legend about stone giants. At first, only Rickey can make out the strange creatures, but as time passes, more and more townspeople catch sight of and sense the danger. Even the landscape and weather around the town begins to change from a mountainous spring chill to that of a tropical forest. Readers are in for a "prehistoric" lesson as Rickey discovers firsthand the age-old adage to be careful what we wish for-it might just happen.