Carleton Coon's books were popular when I was first getting interested in anthropology in the sixties, and I read them with interest. He boldly addressed questions about race that others shied away from. In this book you will find data-supported speculation on how differences in skin and eye evolved, and even in possible differences between races in hormonal development. For that I give him four stars.
Even then, as a teenaged scientist, I realized that Coon's reasoning was flawed. He never said so outright, but he evidently wanted the races to be as separate as possible. Coon argued that the races have been distinct for a very long time indeed, that each evolved into Homo sapiens separately from Homo erectus. Their development would have been a remarkable example of parallel evolution, one that would invite the interpretation that perhaps some races have evolved further than others. But it is incredibly unlikely that every race would have developed from one species to another independently, and molecular genetics has put this hypothesis to rest at last; there is no question now that we are all descended from one Homo sapiens stock. I was not surprised to find later that Coon argued against the integration of schools. If you are interested in the history of anthropology, do read this book, but with caution.
This is easily the best, post-modern tome (of) rationalist theories on racial origins I've ever read. Carleton Coon's objectivity qualifies him as a rare philanthrope. A curious pursuer of revelations.