BOOK REVIEW: MEMOIRS : An Intimate Yet Discreet Look at an Icon of the Theater : MY LIFE WITH NOEL COWARD b<i> y Graham Payn with Barry Day</i> , Applause Books $24.95, 341 pages, illustrated

Intimate but discreet, casual and affectionate, this memoir by Noel Coward’s companion for 30 years delivers exactly what the title promises. Enlivened by photographs and a selection of Coward’s personal essays, “My Life With Noel Coward” lends an added dimension to the playwright’s popular image.

Coward wrote sophisticated comedies of manners, and if those plays now seem precious or quaint, it may be only because the 1930s, ‘40s and ‘50s are not quite far enough away to give us the necessary perspective. In another decade or so, doctoral candidates will be solemnly deconstructing the Coward canon, unearthing layers of meaning that would have gratified and delighted the author, a man intensely conscious of the porous border separating comedy from tragedy.

That narrow corridor was where he chose to live and work throughout his career as actor, playwright and lyricist, though those were merely the public facets of his personality. There was also another, more private vocation, which Payn documents with immense pleasure. Coward was one of the great hosts of the century, constantly filling his spacious houses with friends and acquaintances who could be counted on for scintillating companionship.

Heaven help the guests who let him down, bored him, or failed to live up to their reputations. After the parties were over, Coward, Payn and the select circle they called “family” would demolish the notables, and the passages in which Coward comments on Winston Churchill, the Duke and Duchess of Windsor, and the Queen Mother are among the most amusing in the book.

His appraisals of icons of the theater may be even more appealing to American readers, since we’re far more familiar with Gertrude Lawrence, Vivien Leigh, Laurence Olivier and Marlene Dietrich than we are with the last generation of British royals. A diligent diarist, Coward made sure that his observations would be preserved, and since Payn was present at most of these occasions, his own recollections help to turn the brief entries into small playlets.

As he grew older, Coward became painfully aware that he might be outliving his era. In his 60s when the musical “Sail Away” opened in New York in 1961, the show and its author were dismissed as frivolous and superficial. As Payn says, “What had been ‘light’ was now ‘slight,’ and the bandwagon began to roll backwards.” The critical consensus was that “Sail Away” was 30 years out of date. Payn adds: “In 1936 it would have been the best musical of the year. In 1961 it ran for five months.”

After two decades of exposure to innovative “book” musicals such as “Carousel,” “South Pacific,” “West Side Story” and “The King and I,” American audiences had outgrown the revue format in which the plot is merely incidental to the songs, if not altogether dispensable. When “Sail Away” opened in London, it was soon obvious that British taste had been affected, for better or worse, by Yankee imports.

Coward became pensive and a touch curmudgeonly. “I don’t care for the present trends either in literature or the theater. Pornography bores me. Squalor disgusts me. Garishness, vulgarity and commonness of mind offend me. . . . Subtlety, discretion, restraint, finesse, charm, intelligence, good manners, talent and glamour still enchant me.”

Those endearing qualities seemed to be temporarily out of fashion, and Noel Coward became the theatrical equivalent of the captain of a dirigible. “I have already risen up and twitched my mantle blue,” he said. It was one of his favorite catch phrases, a perfect illustration of his state of mind, which was never nearly as flippant as it seemed.

There would be another decade, a revival of interest in the plays, and the long-awaited knighthood before the Coward show finally closed in 1972. Members of the “family” continued to visit him in Jamaica, and the conversation was as lively as ever, though the parties ended earlier. At the memorial in Westminster Abbey, the Queen Mother herself, Coward’s favorite royal, unveiled the headstone, and a small orchestra played the theme from Coward’s song “Bitter-Sweet.” Coward couldn’t have asked for a finer theater or a more appreciative audience.