Meet the coelacanth, horseshoe crab, dragonfly, tuatara, nautilus, and Hula painted frog. All are living fossils, or modern-day animals that very closely resemble their ancient relatives. Why have they changed so little over time, while other animals evolved or went extinct? Using contrasting "then" and "now" illustrations, veteran nonfiction writer Caroline Arnold alternates between a prehistoric creature in its native environment and its contemporary living-fossil counterpart.