The Psychology of Investing (ISBN 0130930245)

Sometime psychologists confuse logic with emotions:
The book is worth reading and studying for any serious investor. However, the researchers cited assume causality too much. For example, they assume that if an investor sells on gains and holds if a stock has gone down that the investor is afraid to admit defeat. That could be true, or the investor may have a deliberate strategy to "wait out" dips in price until s/he can sell at a gain. Or, the investor could have looked at earnings and business soundness and logically concluded that "Mr. Market" will recognize the higher value of the stock at some point, so why sell now? All of this depends on the strategy you're following, and what your rules of investing are.

Simple, straightforward, but good points:
Kind of a basic look at behavioral finance. Easy too read, not very long (approx. 110 pgs). Overall a good introduction to the tendenecies people have when investing.

Simple and best book about behavior finance:
I purchased this book for my Behavioral Finance class and I have recommended this book to other investors and they loved it so much they bought their own book.

Good overview of the literature of the field:
Nofsinger is a good although not exhaustive overview of the literature on behavioral finance. Used at universities but easy and fun to read. Recommended.

Good Overall:
I got this book in a decent time period and the condition was great.