In a lifetime of writing biographies of famous men, Meryle Secrest has been tempted on more than one occasion to do away with their surviving wives. Widows are the inconvenient keepers of the flame, who watch over the biographer’s shoulder and forbid forays into intimate matters that might compromise the reputations of their husbands. For Ms. Secrest, “widows” are not simply the spouses of dead subjects: They are anyone who might block her access to private papers and privileged information.

Having written lives of Leonard Bernstein, Stephen Sondheim, Salvador Dalí, Frank Lloyd Wright, and other celebrated figures, Ms. Secrest is more than qualified to bring us behind the scenes to witness the hazards and frustrations of the business. Her new book, “Shoot the Widow” (Knopf, 256 pages, $25.95), chronicles her mood swings, false starts, and — above all — delusions that her subjects can be easily snared.

Sometimes it begins well. For her biography of Sir Kenneth Clark, the august art historian, Ms. Secrest initially had her subject’s cooperation. “Say what you like,” Clark’s son told Ms. Secrest. But family members rarely mean it when they endorse openness. They admire your work, what you have done with some othersubject, but then they discover that you have got it all wrong when it comes to themselves!

Sir Kenneth tried to control everything — even paying some of Ms. Secrest’s interviewees on the sly. Such maneuvers lead subjects to believe they’ve got their biographer in pocket. But, as Ms. Secrest illustrates, they must part ways when the biographer asserts her independence.

How do biographers get into such fixes? Ms. Secrest explains: Biographers want access. They are agreeable. They seem like good friends. But to write a credible life they have to get the goods. Subjects as sophisticated as Sir Kenneth might be assumed to have wised up: The biographer, in the end, cannot be controlled. “To hell with you all,” Ms. Secrest finally had to tell his family. Only then could she write her book.

But how could a writer as professional as Ms. Secrest repeat her errors? Ah, that’s where the self-delusion comes in. This time it will be different, the biographer thinks. I have such a good subject and great access! Well, there is no access without acrimony — a truth understood only in retrospect.

Ms. Secrest writes beautifully and perceptively. Her description of a dying Dalí (she got to see him only once for an unauthorized biography) is harrowing. Stripped of his joie de vivre, Dalí was barely able to talk because of the thick tube in his nose. When Ms. Secrest tries to interview him, she finds the layers of his personae had shriveled to a shrunken figure. And yet she describes the scene so vividly and with such a delicate attention to pathos that she conveys a great deal about Dalí in his final days.

Ms. Secrest has alternated between dead and living figures, choosing her subjects according to her interests and what she thinks the market will bear. She is honest about her miscalculations, and even admits to a certain flatness that enters her prose where she has not been able to capture her subject.

I would argue with only one of her opinions. In her biography of Mr. Sondheim, she decided not to pursue the composer’s sexual experience. She equates interest in sex with the trend toward salacious biographies critics have recently deplored. But surely the sexual nature of a subject (alive or dead) is, to modern minds, a part of the whole person.

But would Mr. Sondheim have been so cooperative if Ms. Secrest had done a “Kitty Kelley” (her codename for salacious biography)? Putting aside what I see as an injustice to Ms. Kelley’s unauthorized biographies, it seems to me that in this case Ms. Secrest paid too dearly in this case for her access. Perhaps she was spooked early on when playwright John Guare pointed out to Mr. Sondheim that Meryle Secrest’s name is an anagram for “merely secrets.”

I suspect Mr. Sondheim subtly restricted Ms. Secrest by suggesting she was only interested in secrets. She then had to prove how high-minded she was. This is a common enough trap for biographers, but it’s better to risk full disclosure and the inevitable name calling (James Joyce called them biografiends) than capitulate to the kind of propriety that dooms biographical truth.

crollyson@nysun.com