This book aims to show that, contrary to the received wisdom, the ideas of the two most influential thinkers of the modern age were not by definition antagonistic or antithetical, but are in fact part of a neglected whole only now being unearthed by a new breed of scientist. Sigmund Freud and Charles Darwin created two of the most fertile and most controversial academic fields known to man - evolutionary science and psychoanalysis. Their followers have always considered the other's ideas at best irrelevant, at worst nonsense. Now, all this is changing as the two fields realize that there is much more to be gained by comparing notes and pooling knowledge than by denouncing each other. Badcock has long been at the forefront of what is coming to be called the evolutionary psychology movement, and he proposes in controversial fashion that Freud is nothing if not Darwin's true heir. Badcock straddles disciplines to teach biologists about Freud and psychologists about Darwin, and that is also his purpose in this book. It should appeal to those who would buy a book on Freud but not Darwin, and vice-versa. This book unveils a possible exit from the impasse in late-20th-century thought by showing how analyzing the interplay of genes and human behaviour can bear stimulating and exciting fruit. It is written in a straightforward, jargon-free way, to appeal to the uninitiated, and uses computer games and natural metaphors alongside suggestive diagrams and illustrations to highlight its themes.