Elliott Wave Principle: Key To Market Behavior By: A.J. Frost & Robert R. Prechter
Elliott wave principles are used to analyze the markets and create forecast of the guiding trends by identifying the extremes in investor psychology, price bounds and a variety of other factors. One of the guiding principals is that the crowd (or collective investor) moves between optimistic and pessimistic views in a moderately predictable fashion. Should an investor be able to spot these shifts they stand to profit.
It should be noted that the book is written by Frost and Prechter who are two practicing professionals who have actually used Elliott Waves to forecast market trends. If you're looking for the tools used by practicing professionals to identify changes in the market then this is a great book.