How did Gordon Liddy get Jeb Magruder and John Mitchell to okay the numbskull Watergate break-in? Why did American PeWs in Korea respond to Chinese Communist indoctrination? As self-helpers go, this is both unusually substantive and unusually instructive--it could even save your life. Cialdini, a specialist in social psychology at Arizona State U., examines six ""weapons of influence"" that operate automatically, and which ""compliance professionals"" (con men, salesmen, admen) exploit: reciprocation (if someone has given you a present or don you a favor, you'll probably agree to do or buy something in return, regardless); commitment and consistency (if you've committed yourself publicly, and especially on paper, you're likely to follow through); social proof (if others are doing something, it seems the right thing to do); liking (people we like--because they're attractive-looking, because they're similar to us, or flatter us, or sympathize with us--can get us to do as they ask); scarcity (the scarce--goods, information--is wanted, the suddenly scarce most-wanted). In the case of Watergate, reciprocity was operating in conjunction with ""perceptual contrast"": Liddy had progressively scaled-down his scheme (from the original call-girl/kidnapping/etc. proposal) until it seemed relatively innocuous. In Korea, commitment and consistency were the operative factors: the Chinese secured slight, written concessions--anti-American or pro-Chinese--which, being voluntary (a fascinating, layered discussion), the POWs internalized and added-to. The life-saving stratagem is related to social proof--and the Kitty Genovese murder. It wasn't urban apathy that stopped her 38 neighbors from calling the police, Cialdini finds (as usual, citing research): with so many, the personal responsibility of each is reduced; and, in their uncertainty, all look to the others for expressions of concern. If you find yourself in an emergency, he advises, single out one bystander (""You, sir, in the blue jacket, I need help"") and give precise instructions (""Call an ambulance""); then, others will help too. Also aired: the Good Cop/Bad Cop ploy to get confessions (liking); the grisly Milgram electric-shock experiments (authority); ""the Romeo and Juliet effect"" (scarcity); and much else. A viable, positive way to learn to say no.