“Keepers of the flame” is the term most often applied to the widows of famous figures who safeguard their departed husbands from the depredations of biographers. For more than four decades Kitty Carlisle Hart presided over Moss Hart’s legacy with such style and forbidding authority that no biographer hazarded an unauthorized biography. No one, that is, before Steven Bach, who managed a lunch with Mrs. Hart and was even able to interview her for his biography of Marlene Dietrich. But for “reasons of her own,” Mr. Bach reports in “Dazzler: The Life and Times of Moss Hart” (2001), Mrs. Hart declined to cooperate with his account of her husband.

The fortunate Mr. Bach! It is rare indeed that an authorized biographer, entangled in widow’s weeds,can find an independent route to his subject. As in Henry James’s tale “The Real Right Thing,” the widow stands at the bottom of the stairs monitoring the biographer’s effort to ascend the heights to his subject, a gloomy ghost staring down at him. Mr. Bach did splendidly on his own, drawing on the Moss Hart Papers at the University of Wisconsin and on interviews with Hart’s friends and associates.

“Dazzler” received excellent reviews, and it is a stylish and comprehensive biography that any other biographer has to factor into his own narrative. While Jared Brown does occasionally mention Mr. Bach in “Moss Hart: A Prince of the Theatre” (Backstage Books, 452 pages, $27.95), suggesting perhaps a weakness or two in his competitor’s research, Mr. Brown generally writes as if “Dazzler” does not exist.

But then Mr. Brown has the imprimatur – or at least the cooperation – of Mrs. Hart and her family, who sat for interviews. Did they also vet the biography? I could not tell from Mr.Brown’s account of their involvement in his work.

A reader already familiar with Mr. Bach’s book, however, may detect in Mr. Brown’s narrative an ever so subtle penumbra – rather like a filter applied to a camera lens to blur its focus. Was Hart gay, as some in the theater like Agnes de Mille assumed? Mr. Brown does not mention de Mille in this regard and suggests that not much can be determined about Hart’s sexuality. Like Mr. Bach, he quotes Mrs.Hart’s story that she actually asked her husband if he was a homosexual and that he replied he was not, although he had been the object of a few male passes.

Absent from Mr. Brown’s narrative, however, is any word from Glen Boles, now a practicing psychiatrist, who lived for a time with Hart: “Moss was consumed with his efforts to find his sexuality,” Mr. Boles told Mr. Bach. “He was sexually active but also confused and may have been experimenting.” Such a comment does not settle the matter, but it does make Hart’s saga a more complicated affair than is evident in Mr. Brown’s narrative.

Mrs. Hart told Mr. Brown that her husband did not discuss his many years of psychoanalysis, pointing out that this was privileged information shared by only doctor and patient.Yet Mr. Bach reports, “Boles was privy to details of Moss’s analysis in New York and Los Angeles.” Did Hart wish to spare his wife the details? Who knows? Mr.Brown does not even invite the question.

Mr. Bach’s narration maintains a sharper edge. There is no doubt the Harts had a very happy marriage, but how they came to that bliss becomes a different tale in “Dazzler,” which is the only place you can discover that in a

perhaps unguarded moment (or perhaps not), Carlisle told Barbaralee Diamonstein, then interviewing her for an oral history that can be read but not published during her lifetime, that she had not been in love with Moss when they married. Nor, she believed, was he in love with her. It was the right step for the right people at the right time. It was suitable. The love part could come later.

And it did. But like Hart, who prepared his social life (including his parties) as carefully as he confected his plays, Mrs. Hart stage-managed their lives, as Mr. Bach shows:

There would be no more nude sunbathing parties around the pool. Kitty determined that, whatever people whispered about Moss’s past, his present would be beyond reproach. Sexually ambiguous associates, personal or professional, would have to go, or so the rumor went. Kitty denied it decades later to The New Yorker, causing one exile from Moss’s bachelor days to pop out of the closet and claim he had indeed been banished on Kitty’s orders.

Like Hart’s superb autobiography, “Act One,” everything about the Harts was theatrical, with an air of super-reality. Hart’s great collaborator, George S. Kaufman, thought “Act One” a wonderful book that should have been classified as fiction.

It would be foolish, however, to call the world portrayed in “Act One” false. It is what it is: make believe, like the theater, where enemies greet each other as “darling.” As Joseph Mankiewicz’s 1950 film “All About Eve” shows, this sort of thing goes on all the time. Moss Hart was a persona.

Not that Mr. Brown does not realize as much. One of the virtues of his book is his deft handling of Hart’s diary, in which Hart expressed the anger he never showed even to his closest friends. Hart, the consummate charmer, the “dazzler,” was, in fact, prone to depression most of his life.

But compared to Mr. Bach, Mr. Brown is turgid, especially in his labored conclusion, which almost begs the reader to take Hart’s theater career seriously. Many of Hart’s plays are dated, but he still deserves the accolade Mr. Brown gives him, “A Prince of the Theatre.” His collaborations with Kaufman, especially “The Man Who Came to Dinner” and “You Can’t Take It With You,” are American classics and remain just as funny and as revivable as ever. The latter play, indeed, justifies Mr. Brown’s comparing it with “The Importance of Being Earnest.”

Mr. Brown argues that critics have never taken Hart’s comedies seriously enough. He has a point. “You Can’t Take It With You” is not just a comic romp. It is also an anarchist’s view of society. It features a cast of characters who do exactly as they please; they are a set of nonconformists, a band of originals, who will always be a delight to those wishing to cleanse themselves of society’s smugness and hypocrisy, which is why the comparison to Wilde is so apt.

The cast of characters includes Martin Vanderhof, a wonderfully lively senior citizen who regards social and political developments (such as the income tax) with considerable skepticism; Penelope Sycamore, who writes plays no one will produce (a fate Hart narrowly escaped after Kaufman saw potential in “Once in a Lifetime,” which became Hart’s first hit); Paul, Penelope’s husband, who manufactures fireworks in the basement; Essie, who practices ballet in the living room while her husband, George, practices the xylophone and runs a printing press (with certain slogans that provoke an FBI investigation) – and that’s not even half of the cast.

I don’t think I could have made it through the tedium of high school without this play, or without the inspiration provided by “Act One,” the story of Hart’s yearning to escape into the world of the theater. I know from reading Mr. Brown’s biography that generations of theatergoers, not to mention aspiring actors, have been similarly stirred.

A play such as “You Can’t Take It With You” is a rarity – one that Hart never would equal.Indeed,by the age of 40 his comic genius – in so far as playwriting is concerned – deserted him. But then he went on to write screenplays such as “A Star Is Born” (the version with Judy Garland and James Mason) and to direct plays, triumphantly ending his career with two masterpieces, “My Fair Lady” and “Camelot.”

As the biography of a career, Mr. Brown’s book is a valuable addition to the history of American theater, but as a contribution to biography, I have to award Mr. Bach’s “Dazzler” pride of place.

crollyson@nysun.com