You might not learn everything you ever wanted to know about celebrated writer J.D. Salinger from Shane Salerno’s long-in-process documentary—which serves as an adjunct to a biography by Salerno and David Shield being published simultaneously with its release. But if you’re a fan of “The Catcher in the Rye” and the Glass family pieces that Salinger wrote before disappearing from public view (and the publishing world) in 1965—and as the film shows, some of those fans are fanatics, and have become virtual stalkers of the author—it may tell you more than you would have preferred to hear. It’s a pity that it does so in a fashion that’s too often repetitive and ponderous. But “Salinger” certainly intrigues nonetheless, simply because it opens, at least to some extent, what had long been a closed book.

“Salinger” scores some coups, like offering a clip of the aged author being helped into a car not long before his death in 2010 as well as a shot of him working on “Catcher” while serving in Army Intelligence during World War II. It also insightfully covers his youthful romance with Oona O’Neill, which ended with her sudden marriage to Charlie Chaplin, while persuasively arguing that his first wife—a German woman whom he wed against military policy while in Europe and then divorced shortly after he brought her to the States—had been engaged in problematic activities during the Nazi period. And its treatment of Salinger’s interest in much younger women—there are extended interviews with Jean Miller, whom he met as a teen and adopted as a friend for a few years, and Joyce Maynard, who became his housemate in the 1970s and later wrote a memoir of the experience—suggests a slightly sinister Humbertian quality at work. (Even creepier is Maynard’s revelation that the two of them used to dance to “The Lawrence Welk Show” on television.)

But the biggest bombshell the film offers is the news that Salinger was writing continuously while in seclusion at his home in rural New Hampshire, and that the safe there contains a stack of manuscripts awaiting publication beginning in 2015. If that’s true, it’s a literary disclosure of considerable importance.

But it’s characteristic that Salerno presents this information, which he withholds until the very end of the picture, as a pronouncement of biblical proportions, complete with background music that sounds like fanfares announcing the Second Coming. (And that’s setting aside the unhappy fact that the items listed in the catalogue of coming works don’t sound all that interesting.)

While speculating about Salinger’s unpublished work, moreover, the film gives us very little taste of the pieces he actually did publish during his life. Probably for copyright reasons, there aren’t any quotations from them. Instead we’re treated to comments about them from writers (Gore Vidal, Tom Wolfe, E.L. Doctorow, John Guare) that frankly aren’t terribly enlightening (and are at times backhanded compliments) and enthusiastic panegyrics from celebrities (Martin Sheen, Edward Norton and John Cusack among them) whose remarks seem like padding. As a result, a viewer had better know Salinger’s work in advance, because he’s not going to learn much about it from the film. Still, the interviewees’ words are relatively harmless compared to the awful “dramatic recreations” that show the author fleeing from a publisher’s office or stalking through the New Hampshire woods.

Elsewhere Salerno offers interviews with interlopers upon the writer’s solitude—photographers who staked out his home or the nearby town to snap a shot of him, or overwrought fans determined to talk to him, presumably to learn the life secrets he could impart like some oracle. These add little to the film’s argument, other than to act as a contrast to the fact that some of his friends point out that he wasn’t really a recluse, but only a person who valued his privacy. And though the interviews with friends are sometimes revealing,the lack of participation by Salinger’s children—the remarks of his daughter Margaret come from old television interviews—accentuate the hole at the film’s center. And then there’s the emphasis put upon Salinger’s embrace of Hinduism and his practice of yoga—something that could be truly revealing if it were treated with more than the cursory mention it’s allowed here.

In the final analysis, this is a film that buries a few nuggets in a mountain of repetition and extravagant overstatement. An hour episode of “Biography” would have been a better bet, but a mere sixty minutes would probably not have justified nine years of Salerno’s labor of love—or obsession.