More than half of this study of "the pursuit by governments of policies contrary to their own interests" deals with the United States and the war in Vietnam. Shorter comparative case studies analyze the Trojan horse disaster, the failure of the Papacy to deal with the Reformation, and the loss of the American colonies by the British. The book is in the Tuchman tradition: readable, entertaining, intelligent. It should lead a wide audience to think usefully about "the persistence of error."