Draws on the work of geologists, botanists, marine biologists, and other researchers to discuss the five devastating mass extinctions on Earth and predicts the coming of a sixth.

"The fascinating lives and puzzling demise of some of the largest animals on earth. Until a few thousand years ago, creatures that could have been from a sci-fi thriller--including gorilla-sized lemurs, 800-pound birds, crocodiles that weighed a ton or more--roamed the earth. These great beasts, or "megafauna," lived on every habitable continent and on many islands. With a handful of exceptions, all are now gone. What caused the disappearance of these...

When a meteor shower destroys their home, Aladar and his family join a herd of dinosaurs and must stand strong amidst supply shortages, the threat of carnotaur attacks, and Aladar's run-ins with the herd's stubborn leader.

Twelve-year-old twins Nick and Eryn investigate why their mother and new stepfather are keeping secrets, why they are forbidden to meet their stepsiblings, and, most important, why their lives are in danger.