Daniel Nettle's writing is clear, attractive, and sometimes pleasantly humorous. He takes us through the emerging consensus on the 5 dimensional model of personality, with the genetic explanations, the neurological evidence, and some convincing speculation on the evolutionary reasons for how those dimensions, and the wide variety of scores along them, arose and continue. This is a wonderfully calm and compelling, and very human, book, for the major part of it which covers these aspects. I found, however, the small section on the possible explanations for the non genetically determined aspects of personality oddly frustrating. Nettle examines some potential factors, then demolishes each of them in turn, leaving us with pretty much no explanation. One reason may be that he requires a valid non-genetic factor influencing personality to 'make evolutionary sense', which is a way of ensuring that any candidate factor that passes the test can, hey-presto, be explained by genetics.
The 'bombshell', and it is major, concerns parental influence on personality, but I won't give any plot spoilers here.
His final section, on how to live with your personality once you've got it, is moving, illuminating, and convincing.
A great read for anyone who's either plain curious or looking for solid ground in the sea of 'psycho-babble'.

If you are a fan of evolutionary psychology, be sure to check out this great little book on personality. It has a short personality test (12 questions) that you can take before you dive into the book, which I highly recommend taking. Then you'll learn about each of the "big five" components of personality. Each component is convincingly tied to biological systems in the brain, and the author explains how both high and low scoring individuals in each of the five areas could have thrived as humans evolved.