What happens when one biographer laps another? Mary Dearborn’s compact biography (Houghton Mifflin, 400 pages, $28) appears just about two years after Anton Gill’s heftier “Art Lover: A Biography of Peggy Guggenheim.” Unfortunately, Ms. Dearborn does not answer the above question. Although she refers to “earlier biographies,” she acknowledges Mr. Gill only in her bibliography.

But to begin with, Ms. Dearborn has the better title. She also has a gift for pinpointing her subject’s importance at every turn. Her subtitle is an apt double entendre, for not only did Peggy Guggenheim use her modest fortune to further the cause of modern art – establishing galleries in London, New York, and Venice – she bedded many of the artists she promoted. Art became a way of life, a form of sensual pleasure, and a bulwark against what Guggenheim herself called her “inferiority complex.”

Both biographers see their subject sympathetically and do not dwell unduly on her failings. In Ms. Dearborn’s clean narrative, the shape of Guggenheim’s life emerges with great force. Half the book takes up Guggenheim’s first 40 years, when she struggled to break from her family background – wishing neither to be a pampered wealthy woman nor a conventional member of her class, the offspring of Jewish peddlers and manufacturers who expected their females to decorate but not design their world.

Peggy was the poor Guggenheim. She had nothing like the $30 million to $70 million that her artist-friends confidently supposed she did when they asked her for money. Yet she gave and gave, supporting Emma Goldman, Djuna Barnes, Jackson Pollock, and a host of other artists, who often repaid her with gossip about how she did not give enough, or gave grudgingly. It is hard to know how much money Guggenheim actually had at any one time – it is not clear that she herself could figure it out – but Ms. Dearborn notes that, after her mother died in 1937, her subject had something like $500,000 a year to do with as she liked. It was enough to live well, but not enough to buy the more expensive works of art collected by her Uncle Solomon, who remained indifferent, if not hostile, to her own ambitions.

For a third of Ms. Dearborn’s book, Peggy Guggenheim is a pretty sad case. Although her aesthetic interests developed early, she had no model and no source of encouragement. Her mother was hopeless, and her father died on the Titanic – like a gentleman, in his evening clothes, helping the women and children into the lifeboats. Peggy was only in her early teens when her father drowned, and it is trite but true to say that she spent another three decades looking for his replacement.

Each man she picked seemed dashing and talented enough, but like her first husband, Lawrence Vail, they beat her and used her as a sponge, bringing out what both biographers refer to as her masochistic streak. In these years Peggy herself seems to have thought she was simply not good enough for her mates – or for any artist. Else, why would she put up with the tiresomely critical and ungrateful Djuna Barnes, who drank herself to death while explaining to Peggy that her patron’s life was a mess?

What kept Peggy going through this long day’s journey was a vague yet powerful desire to create a community of artists – an alternative world to the Guggenheim milieu of making money and doting on Old Masters. She did not want simply to own art and artists; she wanted to do nothing less than create a revolution in the consciousness of her time.

Two of the 20th century’s greatest artists, Marcel Duchamp and Samuel Beckett, seem to have provided the support Guggenheim sought but never quite received from others. Duchamp did not patronize her. He did not need her money. And although they had a very brief affair, sexuality had little to do with their interest in each other. Duchamp was a disinterested artist. He retired early from making art, but remained on the scene to advise Guggenheim – although the authority of the laconic Duchamp, unlike that of contemporaries such as the voluble Andre Breton, arose primarily out of his striking presence. Look for the latest significant development in modern art, and Duchamp was there. Guggenheim had the good sense to observe him while others only talked a good game.

Beckett, on the other hand, may have been the love of Guggenheim’s life. As she put it in her candid memoirs, “To begin with he was in love with me as well, and we were both excited intellectually.” This claim, Ms. Dearborn reports, has been ridiculed, yet “there is no reason to doubt this statement, though Beckett’s three biographers do, refusing to believe that Beckett’s emotions were ever engaged by a woman like Peggy, whom they write off as ugly and almost comical.” Peggy was renowned, unfortunately, for her bulbous nose, evidently made worse by botched cosmetic surgery. But she had a good figure, a sexual aura, and certainly no trouble attracting dozens of men to her bed.

But intellectual? Why not? Duchamp never gave any evidence of thinking that Guggenheim could not understand him. Ms. Dearborn notes that the Guggenheim-Beckett liaison lasted 13 months, and that the lovers had trouble parting, even though both realized for a variety of reasons that it would be impossible to make a life together. Ms. Dearborn sums up their affinity this way: “They shared a predisposition for the absurd and a distrust of authority and conventions. Both valued the spontaneous, and both had impressive intellectual energy. They were both funny, in unexpected and understated ways.”

And what of Anton Gill’s view? For it is curious that Ms. Dearborn has space to attack Beckett’s biographers but no room at all for her predecessor, who writes of Beckett: “He was attracted to Peggy because of her vivid personality and her independence of spirit, and because she was sexually liberated: She didn’t disguise what she wanted. Her knowledge of literature was wide, and they shared an interest in modern art.”

Why Ms. Dearborn does not cite Mr. Gill is puzzling. He complements but by no means supersedes her. They differ only in so far as he has a penchant for telling the reader more about the figures surrounding Guggenheim – so that, for example, we learn more from Mr. Gill about Beckett himself and about the need Guggenheim filled at that precise moment in Beckett’s life.

Biography, as I have written often in this column, is not about exclusive rights to a subject. It is a cumulative and incremental story, a beast with many backs. The long and short of it is that Peggy Guggenheim, a kind of monster sacre, has been unusually well served by her biographers.