As a practitioner of psychology, Kahneman was baffled when he encountered the assumptions that underlie economics. The rational beings economists had designed their theories around were not the same beings Kahneman had been dealing with in his multitude of experiments!
Kahneman spends some time describing Bernoulli's Expected Utility Theory as a breakthrough that correctly predicts a number of behaviours. But it has a number of flaws, including the fact that it doesn't take a reference point (i.e. someone's current wealth) into account.
Kahneman's Prospect Theory is more complex as it requires a reference point, but it makes better predictions where Utility Theory fails. In addition, it incorporates the fact that humans appear to hate risk more than they like gains.
Finally, Kahneman discusses the ins and outs of the Endowment Effect.



If I get a chance to rename this book; I'll call it as "Why We Do; What We Do". I loved the concept, presentation and detailed discussion with nice examples for almost all concepts in this book. For me this book is a handbook to try to find out about the reasons behind my past decisions and to understand behaviors and day to day events.
A must read for all.