In the April 11, 2016, issue of The New Yorker, the fabled journalist Gay Talese, at the sprightly age of 84, published a luridly provocative article entitled “The Voyeur’s Motel.” In it, he presented the strange chronicle of Gerald Foos, a man who in 1969 purchased a 21-room roadside motel on the outskirts of Denver and, with the full cooperation of his wife, spent years — decades — spying, every night, on the motel’s guests. He did it by peering down through fake ventilation grills that ran along an elaborate catwalk he’d built expressly for that purpose. Was this ardent Peeping Tom, asked Talese, “a version of Hitchcock’s Norman Bates?” Or was he, instead, “a harmless, if odd, man of ‘unlimited curiosity’?”

The article, and the controversial book from which it was excerpted, hammered on that question in a fearless, probing way. It was an intimate feat of journalistic daring — a high-wire study written by a master reporter-observer. But “Voyeur,” the new documentary about how Talese came to write that story, isn’t nearly as provocative. It offers a sprightly glimpse of Talese’s life and career, and it lets us spend a fair amount of time with Gerald Foos, who turns out to be a friendly bearded Middle American galoot who comes off less as a poster boy for perversion than as a stubbornly “normal,” rather unyielding customer. He’s like a suburban WWII vet who will tell you exactly what it’s like to be a soldier except for, you know, the combat part; that’s left off the table.

After Talese’s article appeared, the rights to it were snapped up by Steven Spielberg, who planned to produce a dramatic feature based on it, with Sam Mendes directing. The project fell through as soon as they learned that this documentary was being made. But perhaps Spielberg and company should have pressed on. “Voyeur” presents itself as a study of obsession, but the quality of obsession is what’s missing from the movie. The filmmakers, Myles Kane and Josh Koury, are too enthralled with the pun of their title: The film is about a compulsive voyeur — but Gay Talese, the man reporting on the voyeur, is a voyeur too! How awesome is that?

Actually, it’s a rather facile metaphor, since so many reporters, and certainly the great ones, have a cultivated tinge of the voyeur about them. In “Voyeur,” we learn all there is to know about Gerald Foos except for the central perverse mystery of why he did what he did. Talese, if anything, emerges as the film’s more intriguing subject, but he, too, isn’t sharing any deep secrets. “Voyeur” has a surface intrigue, but it treats Foos’ highly resonant sicko sociopath’s story as a hook, rather than giving it the full dignity of its indignity.

There are only a few journalists in America who are so esteemed — and well-dressed — that they attain the status of aristocrats, and Gay Talese is one of them. In the ’60s, he belonged to that rarefied circle of writers (Tom Wolfe, Hunter S. Thompson, Joan Didion, Norman Mailer) who elevated reporting into a literary form, and part of what gave these New Journalists their cachet is that they never lost touch with the hard-digging, immersive, shoe-leather side of getting the story. In 1981, though, when Talese published “Thy Neighbor’s Wife,” his book-length investigation of sexuality in America, in which he took his own personal dive into the subculture of swinging, it raised a lot of eyebrows. Appearing on talk shows in his three-piece suits, still the picture of upper-crust establishment refinement, only now with a not-so-hidden kinky air, he seemed a total anomaly: a Tom Wolfe who’d taken a walk on the wild side.

He’s still jazzed by that side of things, but “Voyeur” reveals Talese to be a moral adventurer who, on some level, remains a product of the straitlaced ’50s, which is part of why Foos’ story struck such a chord in him. In 1980, Foos wrote Talese a letter, telling him about everything he’d done, and Talese was fascinated enough to engage in a correspondence with him; he then flew to Denver to meet him. The man he encountered saw himself as a homespun Alfred Kinsey, an impromptu sex researcher who was driven to spy on people for his erotic gratification, but also to feed his consuming curiosity.

He wrote notes on everything he saw, thousands of pages of them. Each night, he was watching life — private, sacred, real — unfold. He saw adultery, debauchery, banality, and a murder. You might say that he was treating life, in an adjoining series of anonymous motel rooms, as his own multi-channel porn hub. You could also say that he was anticipating the whole thrill of reality culture, and seeing it in a more pure form than any semi-rigged TV show is going to give you.

But we have to extrapolate all this, because Gerald Foos, at least in “Voyeur,” doesn’t offer much in the way of self-analysis. He comes off as a more eloquent spokesman for the forbidden lure of looking in Talese’s article and book. The movie finds its drama, instead, in the wary seductive dance between journalist and subject. The more we see of it, the clearer it becomes that Talese, with his dry-martini formality, became a kind of friend to Foos, but that he was also possessed enough by his work that you could say he spent 36 years cultivating him as a source.

The other drama is the semi-scandal that arises out of the book’s publication, when a reporter from the Washington Post unearths inaccuracies in Talese’s reporting. It turns out that Foos sold the motel during the period when he still claimed to be using it for his nightly peep shows. There are other inconsistencies, like the issue of why Foos’s voyeur diary entries date all the way back to 1966 — when he didn’t purchase the motel until three years later. Did he make it all up? Talese acknowledges in the New Yorker article that he considered the possibility that Foos was a “fabulist.” But had one of the high priests of New Journalism been duped? For a suspenseful moment or two, it looks like his credibility has been shot.

But, in fact, it’s a tempest in a teapot. It turns out that Talese got the essential story, and that the details that weren’t in there (about the selling of the motel) proved to be not so vital. “Voyeur” leaves you intrigued but not fully satisfied. There’s a third voyeur here: the movie itself. It keeps staring, trying to make sense of the bizarre tale it shows us, but it never quite breaks through the glass and touches it.