"In this book, Lynn Margulis and Dorion Sagan present an answer to the one enduring mystery of evolution that Charles Darwin could never solve: the source of the inherited variation that gives rise to new species. The authors argue that random mutation, long believed (but never demonstrated) to be the main source of genetic variation, is of only marginal importance. Much more significant is the acquisition of new genomes by symbiotic merger.".

"The result of thirty years of delving into a vast, mostly arcane literature, this is the first book to go beyond - and reveal the severe limitations of - the dogmatic thinking that has dominated evolutionary biology for almost three generations. Lynn Margulis, whom E. O.

Wilson called "one of the most successful synthetic thinkers in modern biology," and her co-author Dorion Sagan have written a comprehensive and scientifically supported presentation of a theory that directly challenges the assumptions we hold about the diversity of the living world."--BOOK JACKET.