The only complaint I had with this book is that it was less concrete than Ridley’s work with “Genome”. Having finished the book I think a lot of this had to do with the highly theoretical nature of evolutionary history. Ridley uses the book more as a means of painting the evolutionary landscape and outlining the prevalent thoughts in force today and lets the reader come to their own conclusions. Still, the science has serious gaps in reasoning and he does a good job (for the most part) of pointing these out and offering his own personal theories where applicable.