Cialdini explains the psychological principles underlying influence. Each chapter is devoted to a different "weapon of influence": Reciprocation, Commitment and Consistency, Social Proof, Liking, Authority, and Scarcity. For each, Cialdini describes how the "weapons" are exploited, gives experimental evidence showing their power, and gives some hints about how to combat them. On the down side, this is a blueprint for sleazy salesmen and advertisers, but on the up side, it will open the eyes of consumers who read it. This book was not what I was expecting, but it was worthwhile.