Palaeontologist Steve Brusatte takes readers through the evolutionary history of mammals. Starting with the beginnings of mammal ancestors during the age of dinosaurs, Brusatte chronicles how these small, nocturnal creatures survived mass extinctions and eventually rose to dominate the planet. Through scientific discoveries, he explores key developments such as the rise of warm-bloodedness, the evolution of fur and milk, and the diversification into the myriad forms we see today. From the mammoths and sabre-toothed cats of the Ice Age to the emergence of humans, this book reveals the story of how mammals became the rulers of the Earth.