The Age of Mammals: In Europe, Asia and North America is a book written by Henry Fairfield Osborn and first published in 1921. The book is a comprehensive study of the evolution and development of mammals in these three continents during the Cenozoic era, which began around 65 million years ago and continues to the present day. Osborn, who was a renowned paleontologist and the president of the American Museum of Natural History at the time of writing,...