We humans are the inheritors of a dynasty that has reigned over the planet for nearly 66 million years, through fiery cataclysm and ice ages: . Our lineage includes saber-toothed tigers, woolly mammoths, armadillos the size of a car, cave bears three times the weight of a grizzly, clever scurriers that outlasted Tyrannosaurus rex, and even other types of humans, like Neanderthals. Indeed humankind and many of the beloved fellow mammals we share the planet with today—lions, whales, dogs—represent only the few survivors of a sprawling and astonishing family tree that has been pruned by time and mass extinctions. In his acclaimed bestseller —hailed as “the ultimate dinosaur biography” by —American paleontologist Steve Brusatte enchanted readers with his definitive history of the dinosaurs. Now, picking up the narrative in the ashes of the extinction event that doomed T-rex and its kind, Brusatte explores the remarkable story of the family of animals that inherited the Earth—mammals— and brilliantly reveals that their story is every bit as fascinating and complex as that of the dinosaurs. Beginning with the earliest days of our lineage some 325 million years ago, Brusatte charts how mammals survived the asteroid that claimed the dinosaurs and made the world their own, becoming the astonishingly diverse range of animals that dominate today’s Earth. Brusatte also brings alive the lost worlds mammals inhabited through time, from ice ages to volcanic catastrophes. Entwined in this story is the detective work he and other scientists have done to piece together our understanding using fossil clues and cutting-edge technology. A sterling example of scientific storytelling by one of our finest young researchers, illustrates how this incredible history laid the foundation for today’s world, for us, and our future.