Fascinating. Ridley is a great writer, and I very much appreciate his (libertarian leaning) philosophy on life. This book is more of an excuse to discuss 23 interesting philosophical issues that are raised by the study of genetics, rather than an introduction to how genes work on a biochemical level. (I would have appreciated a little bit more biochemical information, because even though Ridley goes out of his way to avoid ascribing intentionality to genes, if you don't know how they actually work on a chemical level, it's hard to see them as anything other than teleological.) All very interesting. I was a little disappointed by the chapter on eugenics: He opens it by pointing out the genetic screening for Down syndrome is effectively a form of eugenics, gives a fascinating history of eugenics, and then comes back to Down syndrome... but shies away from saying anything substantial about genetic screening. And I found his argument on free will hard to follow.