Jackson’s husband was both an ally and an antagonist. They began as soul mates: Hyman had never even met her when, after reading a story of Jackson’s in an undergraduate magazine, he declared he was going to marry her, and he remained an ardent champion. At times, he was a little like Colette’s Willy, nagging her to get back to the typewriter. But they also drove each other crazy. He was fastidious; she was sloppy. In theory he was devoted to the children, but left all the work to her. And Hyman, who objected to monogamy on philosophical grounds, was chronically unfaithful. Franklin says he mostly adhered to a “hundred-mile rule,” scheduling his trysts far from home, and unlike many Bennington profs, he at least waited until his students had graduated before pursuing them. But these affairs caused Jackson great pain nonetheless, especially toward the end of her life, when he actually fell in love with one of his conquests. Neglecting the shift key, as she almost always did, she told him in a letter: “you once wrote me a letter (i know you hate my remembering these things) telling me that i would never be lonely again. i think that was the first, the most dreadful, lie you ever told me.”

Jackson, for her part, once enjoyed a drunken grope, and possibly more, with Dylan Thomas on a winter night in Connecticut, but in general seems less sexually driven than Hyman. There is some evidence, though Franklin dismisses it, that as a child she may have been molested by her Uncle Clifford. In college some people thought she might be a lesbian, though there is even less evidence for that. She had, in fact, an exaggerated fear of lesbianism, and in the late ’50s was sent into a tailspin of depression when she discovered herself mentioned in a scholarly book about lesbian-themed writing. In Jackson’s own work, as several critics have pointed out, sex is mostly noticeable for being so absent. Her characters long for emotional connections but seldom make them.

The story of Jackson’s sad and difficult career is told with more vividness and in some ways with more intimacy in an earlier biography, Judy Oppenheimer’s “Private Demons,” which came out in 1988, and which Franklin, though a careful researcher and fastidious about ­sources, never mentions in the text. But Oppenheimer is a journalist, not a critic, and her book, based largely on interviews with Jackson’s family and friends, is interested more in the life than the work. The value of Franklin’s book, which benefited from access to archives unavailable to Oppenheimer, is its thoroughness and the way she traces Jackson’s evolution as an artist, sensibly pointing out what’s autobiographical and what isn’t. She sees Jackson not as an oddball, one-off writer of horror tales and ghost stories but as someone belonging to the great tradition of Hawthorne, Poe and James, writers preoccupied, as she was, with inner evil in the human soul. But her prose, it should be added, was a lot less upholstered than theirs. What makes her masterpiece, “The Haunting of Hill House,” so scarily effective is its matter-of-factness, the cleanness of its narrative line. That book, a ghost story, is often compared to James’s “Turn of the Screw,” but as in a lot of Jackson’s work, its darkness is partly lifted by a slyly humorous streak reminiscent of Muriel Spark or even the Hilary Mantel of novels like “Vacant Possession,” “Fludd” and “Beyond Black.”

Franklin, more than Oppenheimer, wants to play down the chaos of Jackson’s life, and even suggests that the hurtling back and forth between cooking and cleaning and stolen sessions at her desk may have been as enabling as it was burdensome. Until it wasn’t. Always a heavy drinker and smoker, Jackson, while trying to lose weight, became dependent on pills of every sort, uppers and downers. Her mood swings became more extreme, and in 1963 she suffered a full-fledged breakdown, during which she was not only unable to write, she could barely leave her room. After seeking psychiatric help, she seemed to be recovering, and was happily working again, though also preoccupied with the idea of leaving Hyman and creating a new home somewhere. Then, on the sultry afternoon of Aug. 8, 1965, she had a heart attack and died in her sleep. She was only 48. At the time she was working in what she called “a new style,” on a novel that she hoped would be “a funny book. a happy book.” But her last published story, which came out four months later, was about a solitary New England woman who sent off nightly letters describing the terrible secrets of her neighbors.