Alex McBirney, a retired professor of Geology at the University of Oregon is the author of several books on the history of science, as well as his many studies on volcanology and igneous petrology. He developed an interest in Darwin while working in the Galapagos Islands and learned about Perrier's long-overlooked book through his friend, Philippe Janvier, at the Museum of Natural History in Paris. He saw that it was a very scholarly book of broad interest, but after reading few pages he realized why it had been almost totally ignored. Much of the text is very convoluted and almost incomprehensible, even to native French speakers. Enlisting the help of two colleagues, Gregory Retallack, a paleontologist, and Stanton Cook, a biologist, he undertook the task of translating it into a more readable form, so that it would be available to wide audience. The text has been annotated to take into account more recent work, and an extensive Glossary and Biographical Index have been added to provide a ready reference to the technical terms and persons cited in the text.