This is a book on behavioural economics. That is, the study of how people in the real world make sub-optimal decisions. It sits firmly between Freakonomics and A Mind of Its Own. Stylistically, it sits nearer the former - Ariely is a fairly serious academic, and most of the material is his own research made accessible to the general public. Content-wise, there is much closer affinity with Fine's book. The differences there are that Fine uses a wider range of research, doesn't just focus on economic-style decisions, and is much less hopeful about overcoming our problems. This book is more worthy, but Fine's is more fun.