I read this on the Kindle. Fully half this book is composed of footnotes, citations and indices. This is a very well researched book.

It's also a funny one. The author makes no secret that he doesn't think much of the standard model of human sexuality, but he's at his best when tearing apart a hapless researcher who defines their evidence in terms of the model instead of the other way around. And there's many, many targets to choose from. Not a chapter goes without some new clunker dropped.

There are some places where the author seemingly picks and chooses his evidence as loosely as his targets. notably when he claims that a male preference in porn for many men on a single woman was a result of our innate wiring, because there are more "guy on girl" than "girls on a single guy" videos.

According to the book, female vocalizations (to call other men closer), the slower rampup time and prolonged heat, combined with the capacity for multiple orgasm mean that women, when they felt like having sex, would have sex with one guy and then pick several likely candidates to follow up with if they were still in the mood. Sounds good. So why is this a fantasy for men, when it should really be a fantasy for women?

And that's where it really needs to make its case: one of the premises is that female sexuality has been driven and suppressed to the extent that even when in a study of sexual behavior, the best way to get good statistical data is to tell people they're hooked up to a lie detector, or use data that cannot be faked and does not rely on self-reporting, such as measuring brainwaves or bloodflow. But by using this argument as his yardstick, he's essentially saying that most sex data gathered about western women is skewed, either by the researchers or by the subjects themselves. It's a big argument to swallow, and I'm not sure I entirely buy it. It also doesn't cover the female fascination with romance novels on one end, shading to yoai / slash fiction as it gets more "hardcore." If this is a cultural habit rather than an inbuilt preference, it's a counterintuitive one.

That being said, his general thesis stands up. Daniel Dunbar talks about language as a grooming activity and says its a more efficient replacement than grooming for nits. Ryan says sex itself is a grooming activity, and one that is amazingly effective at holding groups together. After seeing the evidence he provides, I think he's probably right.