WHEN “The Shining” was released in 1980, many viewers, including the critic Pauline Kael, left theaters mystified by what they had just seen. Expecting a standard frightfest based on a Stephen King best seller, they got an unexplained river of blood surging out of hotel elevators, a vision of cobwebbed skeletons and a weird guy in a bear suit doing something untoward with a gentleman in a tuxedo.

Three decades on, scholars and fans are still trying to decipher this puzzle of a film directed by Stanley Kubrick. To them it’s only ostensibly about an alcoholic father, Jack Torrance (Jack Nicholson) going more than stir crazy while his wife, Wendy (Shelley Duvall), and son, Danny, try to cope in an isolated hotel, the Overlook. Mr. Kubrick was famously averse to offering explanations of his films — “I have found it always the best policy to allow the film to speak for itself,” he once wrote — which has led to a mind-boggling array of theories about just what he was up to.

The hotel’s hedge maze, many Kubrick authorities agree, is a reference to the myth of the Minotaur; others have drawn convincing connections between the Overlook’s well-stocked pantry and the confectionery cottage in Hansel and Gretel. The more one views the film — and many of these scholars admit to viewing it hundreds of times — the more symbols and connections appear.

“Room 237,” the first full-length documentary by the director Rodney Ascher, examines several of the most intriguing of these theories. It’s really about the Holocaust, one interviewee says, and Mr. Kubrick’s inability to address the horrors of the Final Solution on film. No, it’s about a different genocide, that of American Indians, another says, pointing to all the tribal-theme items adorning the Overlook Hotel’s walls. A third claims it’s really Kubrick’s veiled confession that he helped NASA fake the Apollo Moon landings...