One of the best of the recent spate of books on terrorism, rich in historical background, penetrating in its analysis of motives, measured in judging the challenge it presents to democratic societies. The author dismisses, rightly, conceptions of terrorists as all demented fanatics, common criminals or hit men directed by Moscow. They are mainly educated or half-educated youths from the upper or middle classes, with serious if unrealistic aims; they exist because political and social conditions have produced them. Taking stock of the various organizations and movements, the author seems on firmer ground with the "anarcho-communists" (Baader-Meinhof gang, Red Brigades, etc.) than with the left-nationalists and separatists, and he rather slights the thriving groups in the Middle East now causing most of the trouble. As for remedies, he finds improved intelligence and police work desirable but insufficient, and counterterrorism-"going to the source," as in the bombing of Libya-a cure that will only spread the disease. His concluding bit of advice will hardly strike Washington as being of much practical help: if Americans are targets of terrorism, it is because they are seen as representatives of imperialist and oppressive policies; to change that, America will have to change its sinful ways.