Noel Coward kept a detailed diary from the early Forties to 1969--he elegantly laid aside his pen when news of his knighthood arrived--but readers in search of new revelations will be disappointed: the Coward biographer, Cole Lesley, had access to the Diaries for Remembered Laughter (1976); and, as far as his own love-life was concerned, Coward was utterly discreet, even in private. (There's virtually only one such reference here--to falling-in-love again at 58: ""I can already see all the old hoops being prepared for me to go through. Ah me!"") Still, if there's no news in these massively footnoted 704 pages, there is wit, hilarity, aphoristic genius, theater-lore, some gossip . . . and magnificent affirmation of Sir Noel's essential decency, compassion, and gentlemanliness--qualities not often associated with the show-biz world. He was conservative, of course, in both art and politics: Waiting for Godot is ""pretentious gibberish,"" Death of a Salesman ""boring and embarrassing""; the assassination of Gandhi is ""a bloody good thing but far too late."" He was not good with children. (On a friend's noisy grandson: ""I should have liked to cleave his winsome little blond head in two with a meat axe."") There are devastating backstage portraits of the leading ladies involved in each Coward show--Bea Lillie, Edith Evans, Claudette Colbert, Lili Palmer (""the mixture of female film star and Kraut is not entirely felicitous""), and sometimes-beloved Mary Martin. There are diatribes against critics, theater parties, Germans, American taste, television, Mary Renault (""Oh dear, I do, do wish well-intentioned ladies would not write books about homosexuality""), campiness, religion, and Graham Greene: ""He has a twisted, tortured mind but, like most of God's creatures, aches to be loved."" There is a good deal of self-deluding explanation for the lack of great success (except as a performer) during these decades. But the combination of common-sense and ever-good-humored eloquence is the dominant tone here--whether following the year-after-year turmoil in the Vivien Leigh/Laurence Olivier marriage or writing, with great patriotic sincerity, about England's decline. And this is, with very few lapses into the usual journal trivia, a Grand Tour of a Diary: an uncommon display of effortless stylishness, a valuable (if joyfully biased) record of transatlantic theater in the postwar period, and an irresistible surprise package overall--cutting, kindly, loyal, vengeful, but always professional . . . and very rarely ugly or sad.