Party Of One OUT OF STEP: AN UNQUIET LIFE IN THE 20TH CENTURY by Sidney Hook Harper & Row; 629 pages; $29.95

By Stefan Kanfer

At 84, Sidney Hook seems to have preserved all and pardoned none -- including himself. If any error occurred in the past, it was duly noted, to be summoned up on some appropriate occasion. Out of Step is the occasion. Hook is currently a senior research fellow at the Hoover Institution on War, Revolution and Peace in Stanford, Calif. All three subjects are specialties of the man who believes that "the central problem of our time is . . . the defense and enrichment of a free and open society against totalitarianism."

He began life in the Williamsburg section of Brooklyn, discovered aspects of the "Socialist dream" in adolescence and taught philosophy at New York University for more than four decades. There, as in such books as The Hero in History, The Paradoxes of Freedom and Pragmatism and the Tragic Sense of Life, Hook established a well-founded reputation as a secular humanist. He questioned received ideas and challenged those who substituted passion for logic. The professor played no favorites, and few were happy with his investigations. To '30s conservatives, he seemed a Marxist apologist; to '60s New Leftists, he was a cold warrior. But as his autobiography proves, the only group to whom Hook paid strict allegiance was the party of one.

The Moscow Trials of 1936 were, he recalls, "a decisive turning point in my own intellectual and political development . . . I never suspected that ((Stalin)) and the Soviet regime were prepared to violate every fundamental norm of human decency that had been woven into the texture of civilized life." Some friends and colleagues remained lockstep Stalinists, and Hook brings them onstage as object lessons. Lincoln Steffens had famously seen the future in the U.S.S.R. and proclaimed that it worked. It was less well known, notes the author, that Steffens "had previously seen it in Italy . . . where he thought it had also worked. His praise for Mussolini was as glowing as for Lenin." Bertolt Brecht told Hook that the status of defendants in the Soviet dock was irrelevant: "The more innocent they are, the more they deserve to be shot." Hook dryly comments, "I never saw him again."

It hardly mattered. There were hundreds of other notables to engage the philosopher's attention. Although he was at constant odds with colleagues like Philip Rahv, Mary McCarthy and Dwight Macdonald, Hook was associated with the opinion molders of the Partisan Review, perhaps the closest thing to the claustrophobic Bloomsbury set the U.S. has ever produced. They wrangled over every aspect of politics and culture, and as the memoirs of the survivors show, after a half-century, sentiments have still not cooled. Particularly Hook's, who now regards the Partisans as the "Radical Comedians" because "there was something truly comic about their self-conscious role as political revolutionaries and cultural radicals; about the disparity between their profession and their performance."

At intervals, the author lowers his fists, but much of the anecdota reconsiders a series of onetime celebrities, hacks and propagandists who have long since been swept into the dustbin of history -- with Hook handling the broom. He was performing those janitorial services at N.Y.U., when classes were shut down during a '60s antiwar protest. Hook was an early opponent of U.S. involvement in Viet Nam but characteristically went on teaching. At one session, he recalls, "three raucous S.D.S. students burst into the classroom, shouting 'Strike! Everyone out!' No one moved. I turned and shouted, 'I am placing you under a citizen's arrest,' not knowing exactly what that meant, and the students fled." The incident is emblematic of the man, always in opposition to the prevailing tempo and, in the end, more durable than his hecklers.

It would be easy to stigmatize Hook as a collector of grievances and negatives. In fact, an almost heroic optimism invigorates his work. Twice in old age, he notes, his heart has stopped, and once he asked to be taken off life-support systems, only to be refused. Yet he feels that "the test of whether a human being has enjoyed a happy life is whether, if it were possible, he or she would accept another round of it. By this test I have had a happy life."

And an exemplary one. The professor emeritus now regards political activism as a diversion from his primary interest in pedagogy. But the conclusion of his 20th book belies that claim: those who are indifferent to vital issues "owe the intellectual and cultural freedoms in which they luxuriate to the commitment and sacrifices of others." Even his extensive list of opponents would have to concede that the spirit of those "others" is crystallized in Sidney Hook's long, retributive and triumphantly out-of-step career.