This is the best book I've read all week (never mind that it's the only book I've read this week). While not philosophy, it should be required for all philosophers who talk about rationality and agency, as well as social scientists, and for that matter everyone. Ariely gives concise and clear descriptions of his experiments going back several years, and extrapolates general forces affecting our choices and motivations. These vary from findings that basically prove what should be common sense (SURPRISE! 20-year old males show impaired judgment when aroused!), to effects that are genuinely surprising (did you know people are almost twice as likely to cheat when the payoff is non-monetary?). Ariely also tries to use these findings to give practical advice for how we can counteract these affects in our decision-making, pointing out that awareness can help but that, like optical illusions, we may not be able to avoid their influence. I picked this up randomly on Saturday and finished 5 days later; if you're not in law school you can probably do it in 2 - and I would highly recommend you do.