Neville Chamberlain's failure to appease Hitler in 1938 produced a seminal lesson in modern diplomacy: concessions to aggressive states invite only more aggression. In this thoughtful reconsideration, Rock argues that little evidence supports this view. Indeed, appeasement can reduce tensions and modify the demands of the aggressor. The book's insights are drawn from a range of episodes, from British appeasement of the United States at the turn of the century to Anglo-American accommodation of the Soviet Union during World War II to American engagement with North Korea under Bush and Clinton. The book offers unsurprising but sensible recommendations, including a policy approach of mixing deterrence with engagement. Simple conclusions do not emerge, although the author does show that the character and motivations of the unsatisfied state matter most in determining success or failure. Rock also does not dispute that Chamberlain's policy was doomed. But he makes the point that other aggressive states, such as North Korea, seem to have more limited ambitions than Nazi Germany -- and are therefore more easily manipulated by inducements.