It was only a matter of time! Sabuda and Reinhart turn their magic on dinosaurs in six dazzling double-page marvels of paper engineering. Each dramatic page is festooned with text, illustrations and smaller booklets, many with their own miniature pop-ups, 35 in all. It's hard to say which we like best: the roaring T-Rex, jazzy blue-green archeaopteryx that flies off the page or dueling triceratops. The Prehistorica series continues with Sharks and Other Sea Monsters (SCI166) and Mega-beasts (SCI273).  (SCI102, $29.99)