Published in 1939 just before Hitler invaded Poland, The Twenty Years' Crisis: 1919-1939 was one of the first modern books on world politics in the classic tradition of Thucydides and Machiavelli. During the long weekend between the two world wars, says British scholar E.H. Carr (1892-1982), there was in the English-speaking world an almost "total neglect of the factor of power." Like Reinhold Niebuhr, whom he often quotes, Carr believes that a balance of power among states is the starting point in foreign policy but that morality is an essential consideration. Utopian "superstructures such as the League of Nations," he said, were not the answer. Carr's critics point to his early pro-Nazi stance and his muddled thinking about communist Russia. He once wrote that "the Russian Revolution gave me a sense of history" and it "turned me into a historian." That said, this book remains a seminal work on the realism that instructed U.S. and British Cold War statesmen.

2. Darkness at Noon by Arthur Koestler (Macmillan, 1941).

Born into a learned Jewish family in Budapest, Arthur Koestler (1905-83) was educated in pre-Nazi Germany. He became a Communist, served as a journalist in the Spanish Civil War and later visited the Soviet Union--experiences that led him to conclude that both fascism and Marxism were evil political religions. Fluent in five languages, he wrote the novel Darkness at Noon, one of the 20th century's most stirring anti-communist works, in English. He said that his characters in Darkness at Noon were fictitious but that "their actions are real," a composite of Stalin's "so-called Moscow Trials" and its victims, several of whom he knew personally. This intimacy with real victims enabled Koestler to make vivid the torture, brainwashing and forced confessions of uncommitted crimes. With consummate skill he underscored the vital moral issues of the Cold War, indeed of the human drama.

3. The Children of Light and the Children of Darkness by Reinhold Niebuhr (Scribner, 1944).

Reinhold Niebuhr (1892-1971), born in St. Louis of German parents, was the best-known American moral philosopher of his time. Following his pioneering "Moral Man and Immoral Society" (1932) and his monumental "Nature and Destiny of Man" (1942), this slim volume, with its primer-like title, may seem like a trivial afterthought. But it is a profound analysis of man and history, and of democracy, then under siege by Hitler and Stalin. Calling his book "a vindication of democracy and a critique of its traditional defense," Niebuhr argues that "man's capacity for justice makes democracy possible; but man's inclination to injustice makes democracy necessary."

4. The Super-Powers by William T.R. Fox (Harcourt, 1944).

William T.R. Fox (1912-88), a Yale scholar, is generally credited with coining the word "superpower" with the publication of this book. Writing even as World War II rages, he invokes classic concepts such as the balance of power to explain the dynamics of the coming postwar world. A morally sensitive realist, Fox castigates dreamers like the Federal Council of Churches executive who in 1942 declared bluntly that "alliances and balances of power . . . are destructive of world peace," and he disabused his readers of any thought that the nascent United Nations would be able to maintain peace and order.

5. The True Believer by Erich Hoffer (Harper & Row, 1951).

Six years after Hiroshima, as the Cold War was revving up, this slender volume by self-educated longshoreman Eric Hoffer (1902-83) came off the presses to immediate acclaim. In idiosyncratic prose, Hoffer offers his "thoughts on the nature of mass movements," from early Christianity to the rise of modern totalitarian states. He condemns with equal fervor Hitler's Germany, Stalin's Russia and Western intellectuals seduced by their own guilt-ridden longings for utopia. Throughout his days as a blue-collar worker, Hoffer said, he "read indiscriminately everything within reach," and he quotes just as freely, from the Bible, Milton, Dostoevsky, Tocqueville, Thomas a Kempis and Yeats. Hoffer, an unabashed American patriot, championed honesty, integrity and the work ethic.

-- Mr. Lefever, a senior fellow at the Ethics and Public Policy Center, is the author of The Irony of Virtue: Ethics and American Power (1998) and America's Imperial Burden (1999).