"Sex at Dawn" ask why monogamy and infidelity are such prominent issues in many societies. They argue that monogamy does not come naturally to our species, but rather is an imposition of the religious and cultural institutions that appeared with the advent of agriculture. These institutions, together with mainstream evolutionary psychology, maintain the conventional wisdom that men and women evolved in families where a man’s possessions and protection were exchanged for a woman’s fertility and fidelity. The authors maintain that this narrative is collapsing, and take a tour of evidence from anthropology, archeology, primatology, anatomy, and psychosexuality to offer data and arguments that our ancestors lived in egalitarian groups that shared food, child care, and often, sexual partners.
I downloaded the book for my Kindle, and found it an entertaining, spirited and engaging read, although it did have its share of inaccuracies, as well as some chaotic, repetitive and preachy sections. Their argument against the conventional evolutionary psychology view as a set of just-so stories is a common one. I would suggest that you glance at the excerpts from the book offered on their website to get an idea of bouncy tone of the prose.