Blue whales have hearts the size of golf carts, while some frog hearts can freeze solid for weeks, resuming their beat only after a spring thaw. In this lively, unexpected look at the hearts of animals—from fish to bats to humans—American Museum of Natural History zoologist Bill Schutt tells an incredible story of evolution and scientific progress. Schutt also traces humanity's cardiac fascination from the ancient Greeks and Egyptians—who believed that the heart contains the soul—all the way up to modern-day laboratories, where scientists use animal hearts as the basis for many of today's most advanced therapies.