Doing Turns on a High Wire THE LIFE OF KENNETH TYNAN by Kathleen Tynan; Morrow; 597 pages; $22.95

By RICHARD SCHICKEL

When the stage was his only world, Kenneth Tynan dominated it as no drama critic since George Bernard Shaw had. When, sometime in the 1960s, the wide world was turned into a stage for celebrity posturings, the critic recast himself as a potential star, offering himself as an international social critic and sexual reformer. And became just another face in a crowd grotesquely clamoring for attention. The life his second wife, Kathleen, recounts in her uncompromising and ultimately harrowing biography-memoir becomes the record of a befuddled search for the fulfillment of youth's inordinate promise, and for the graceful exit Tynan never found.

As a reviewer in London and New York City in the '50s and early '60s, he demonstrated an unequaled gift for capturing the theatrical moment in language charged with wit, passion and a vibrant vision of what theater might be and rarely was (or is). His pieces offered nothing less than his own tumultuously responsive self as the link by which a decaying medium could re-establish its connection with our public lives -- and our secret ones. His elegant disdain helped sweep the boards of the dusty verse drama that then passed for high seriousness, and of the cobwebbed comic conventions that served only a low commercial cunning. His eloquent partisanship opened the doors not just for a new moral consciousness but for fresh forms of theatrical literacy, like Tom Stoppard's bedazzling overstatements and Harold Pinter's hypnotic understatements. At Tynan's memorial service in 1980, the former turned to the critic's children and said, "For those of us who shared his time, your father was part of the luck we had."

Tynan himself heedlessly outraced that luck. Affecting purple jackets and leopard-spot trousers, courting the social and cultural glitterati, restlessly glamour-traveling the world, he made it clear from the start that the critic's customary place as a dim lurker in the shadows was not for him. A bourgeoise childhood (he was the bastard son of a merchant who achieved knighthood) in provincial Birmingham taught him his lifelong horror of grayness. His legendary Oxford career as controversialist, actor, debater, director, dandy and libertine imbued him with his tropism toward fame's warming light. Indeed, it might be argued that his life's central mistake was the innocent notion that he might dominate the great world as he once had the great university.

But a well-thought-out (or at least well-rationalized) principle was operative too. Tynan reserved his deepest regard for what he called "high- definition performers," the elite who communicate the essence of their talents "with economy, grace, no apparent effort and absolute hard-edged clarity of outline." That description perfectly fits his reviews. He was, in them, a man doing turns on a high wire, the light refracting off his sequined prose, half blinding readers already dazed by his fearlessly leaping judgments.

He could coolly build his journalistic successes on the failures of the very performers he was pursuing socially. Vivien Leigh, for example, picked at Cleopatra "with the daintiness of a debutante called upon to dismember a stag." Orson Welles' Othello was infamously scorned as "Citizen Coon." But the courage to assert oneself dangerously for a moment in the spotlight is different from what is required to build less flashy careers or coherent lives. "Rehearse xmas dinner" Tynan ludicrously instructed himself in his diary. Everything had to be a show, and guess who had the lead? In another memo he planned to exhort his first wife, the American-born novelist Elaine Dundy, to "worship me much more plainly."

For all his need to dominate lives and events, Tynan was, as he put it, fundamentally "a watcher, an observer, a reflector," not "an instigator." The attempt to resolve this conflict between desire and gift had a wearing effect on him. His writing after he abandoned regular reviewing, except for some intermittently marvelous collections of occasional pieces, was all false starts. The long line eluded him: the Oxford memoirs, the biographies of Sexual Theorist Wilhelm Reich and Laurence Olivier and his autobiography were all stillborn. His other work was equally frustrating. As literary manager of Britain's National Theater under Olivier, he helped chart a bold course, but was shunted aside by shrewder politicians. His oddly diffident pursuit of directorial assignments in film and theater (which his widow thinks would have restored his battered spirit) came to nothing.

In these straitened circumstances, he became one of the sexual revolution's chief publicists, in the process trading authentic esteem for tabloid notoriety. It is possible he was driven in part by a need to make the world safe for his own secret vice. Both his wives eventually discovered, to their dismay, the little tin box full of the porn he pathetically treasured -- spanking photos. After becoming the first man to utter the f word on British TV and "devising" that quintessential artifact of the '60s sensibility, Oh! Calcutta!, Tynan found a young woman whose masochistic fantasies matched his sadistic ones. The basement flat where they acted them out was the only theater of his late years where he could with impunity act the player king.

He expressed a more disturbing kind of sadism by insistently confiding the details of his extramarital activities to his wife. Kathleen Tynan, a collaborator-victim of the life she chronicles, resists drawing some of the more obviously dismaying conclusions from it. But understated objectivity renders her account of its pitiful conclusion the more moving. In 1976 Tynan exiled himself to Santa Monica, Calif., where he hung out with movie people and wrote a few solid profiles, one of which was about Johnny Carson, whose work he compared, perhaps with nostalgic envy, to that of a daring acrobat. Congenitally predisposed to the emphysema that now racked him, he quietly, ingloriously smoked himself to death, bringing to a premature end (at 53) a life that might have been exemplary but that emerges in this brave retelling as cautionary instead.