The book that I chose for this book review is Thinking Fast and Slow by Daniel Kahneman. He is an Israeli-American psychologist and winner of the 2002 Nobel Prize in Economic Sciences. He is notable for his work on the psychology of judgment and decision-making, behavioral economics and hedonic psychology. The main thesis of the book is quite simple. When judging the world around us, we use two mental systems: Fast and Slow. The Fast system (System 1) is mostly unconscious and makes snap judgments based on our past experiences and emotions. When we use this system we are as likely to be wrong as we are to be right. The Slow system (System 2) is more rational, conscious and slow. They work together to provide us with a view of the world around us. Together, they shape our impressions of the world around us and help us make choices. System 1 is largely unconscious and it makes snap judgments based upon our memory of similar events and our emotions. System 2 is painfully slow, and is the process by which we consciously check the facts and think carefully and rationally. Problem is, System 2 is easily distracted and hard to engage, and System 1 is wrong as often as it is right. System 1 is easily swayed by our emotions. Some examples he cites include the fact that pro golfers are more accurate when putting for par than they are for birdie, regardless of distance, and people buy more cans of soup when there's a sign on the display that says "Limit 12 per customer." An easier way to describe the two systems would be to identify them as subconscious and conscious, though Kahneman does not explicitly make this description. Kahneman notes that even top performers in business and sports tend to revert to the mean in the long run, i.e. regression toward the mean. As a result, he attributes success largely to luck. I am not so convinced of this. There can be alternative explanations. People who achieve high degree of success are also exposed to a high degree of failure and the regression toward the mean may be due to this possible mirror effect. Spectacular success may go with spectacular failure and run-of-the-mill success may go with run-of-the-mill failure. Eventually everyone may regress toward the mean, but the ride can be very different. Chance does not account for that. Furthermore, the theory has holes. It is argued that, since System 2 is where we conduct our rational choices, System 1 must therefore be irrational. And, since we are largely governed by System 1, our actions are based on non-rational processes. Yet, Kahneman neither explains how the different systems arise, nor does he examine what the systems are made up of. He simply shows that people think and make decisions in two different manners. Since Kahneman's work has been so influential, a lot of the ideas presented in the book might not be new. Cognitive biases such as loss aversion, priming, and framing have all been presented and analyzed in nearly every Behavioral Economics book out there. On the other hand, while the ideas are not novel, it is rewarding to read an analysis from the original source of the studies. Kahneman provides insights into the rationale of the studies that other writers could not offer, so this book seems more penetrative than the others. Where his successors string together pieces of interesting yet seemingly incoherent tid-bits about cognition and behavior, Kahneman proposes a much more developed thesis on human cognition. Overall, Kahneman gives a very good review of the subject. It separates our intuitive thought from our reasoning ability. There are some findings that seem surprising until some serious thought is given. My main objection is that the book is quite repetitive. The author seems to go over and over the same or very closely related material. It reads like a scientific paper that has been expanded into book form. Despite its few flaws, this book is written carefully in a rather humble tone. I also appreciated Kahneman's generous and unreserved acknowledgement of Tversky's contributions and his belief that, had he been alive, Tversky would have been the co-recipient of the Nobel Prize. Nevertheless, Thinking Fast and Slow is a very valuable book by one of the most creative minds in psychology.