There are hundreds of books about dinosaurs, popular and technical, but very few about the mammals that followed them. Some are geared for a general audience; some for specialists. Prothero's new book has the advantage of something for everyone, almost. A specialist can read it for a fine overview of many aspects of life throughout the age of mammals; a general reader will get the same overview, plus an introduction to a great many new topics to research further.
Don's strengths have always been in the climatic and faunal evolution of mammals, and the stratigraphic relationships of the deposits in which their fossils are found. This book plays to his strengths, which many of us lack. The result is a comprehensive look at the geology and climate of the Cenozoic Era, including the climatic indicators afforded by isotope studies, invertebrates, and fossil plants. The Age of Mammals is presented here as a series of subdivided slices of time, each with its own distinctive climates, geological circumstances, and faunas.
This is about the most readable volume imaginable in what is one of two classic approaches to the history of life: either one goes group by group or one goes through the time column successively. Because Don takes the second approach, there are hardly any cladograms in the book, and not much discussion of phylogenetic relationships or evolutionary adaptations. There are many reproductions of artists' reconstructions of fossil mammals, but very few skeletons and almost no drawings of teeth, which are the stock in trade of mammalian paleontologists. On the other hand, this is a great source for understanding geological and climatic change, and its effects on the faunas and floras of the Cenozoic Era — a comprehensive coverage found in almost no other book.
This is perhaps not the source to take anti-evolutionists to if you want to explain to them the fine points of how whales evolved from terrestrial animals. On the other hand, this book is unusually good in showing how a great many lines of evidence — from chemistry, physics, astronomy, geology, botany, and climatology — contribute to a unified picture of the history of life that accompanies the fossils in the rock record.