Ultimately, the more you know about William S. Burroughs, the less you’ll get out of the new documentary “William S. Burroughs – A Man Within.”

If you don’t know much, or much beyond the fact that he’s the vaguely infamous author of the novel “Naked Lunch,” the movie will be a real eye opener.

If you know that he was one of the Beats, was a lifelong heroin addict and alcoholic, was adopted as a spiritual godfather by the ’70s punk rock movement and, while an outspoken homosexual, was once married (and accidentally shot and killed his wife, Joan, while playing a drunken William Tell game with a loaded gun), you’ll have your understanding of the man’s life shaded in through rare documentary footage and the reminiscences of friends and admirers. (I was surprised to learn about his lifetime gun obsession; he even received a huge handgun as a present from fellow cult figure Hunter S. Thompson.)

But if you’ve actually read Burroughs’ works – “Naked Lunch,” “The Ticket That Exploded,” “Junky,” “Queer” and others – and are looking into some penetrating insight into those books and their author’s importance in the 20th-century literary scene, well, you’ll just have to take those admirers’ words for that.

It’s not that “A Man Within” (showing Wednesday at Space Gallery as part of its ongoing artist documentary series) is a bad documentary, or a bad document of Burroughs’ life. It’s actually a pretty engrossing and moving account of the life of a brilliant, uncompromising, complex and, ultimately, very lonely man.

It’s just that, at a brisk 87 minutes, it’s both too sketchy and too interested in portraying the notoriously prickly Burroughs as something of an old dear.

Not that I mind the sentiment (as I am a huge, huge softie). The interviews with fans and contemporaries such as Laurie Anderson, Gus Van Sant, David Cronenberg and Peter Weller (the director and star, respectively, of the film adaptation of “Naked Lunch”), Amiri Baraka, Iggy Pop and others are uniformly affectionate and revealing about his perpetual “apartness,” no matter how many literary or social movements tried to claim him.

I was especially moved by the insightful thoughts from musician friends Patti Smith (who used to sing Burroughs children’s songs on request) and former Throbbing Gristle frontman Genesis P-Orridge.

And isn’t the world an unexpectedly better place now that former fellow outcast John Waters has become a wise voice of reason? (Plus, it’s pretty adorable the way almost everyone lapses into an impression of his trademark sepulchral, singsong-y way of speaking.)

But there was more to the man, and, apart from some generalities (one biographer calls him “the most important American writer of the second half of the 20th century”), his work gets short shrift, and even some details of his hard-to-believe life are glanced over. I suppose it’s a compliment to say I wish “A Man Within” were a half-hour longer. But, then again, it isn’t …

Dennis Perkins is a freelance writer who lives in Portland.