"Vito," a Documentary About Vito Russo, on HBO Richard C. Wandel and the LGBT Community Center National History Archive/HBO The HBO film "Vito" profiles Vito Russo, center, the gay activist and author of "The Celluloid Closet," who died in 1990. After watching "Vito," a documentary about Vito Russo on Monday night on HBO, you might be tempted to think, "Wow, that was an amazingly full life." But really it was a life cut short: Russo, a film scholar and gay-rights activist, was 44 when he died of AIDS in 1990. The film, by Jeffrey Schwarz, makes you feel the loss. The likable, energetic gadfly who emerges here would have been a great voice to have on hand today, providing an informed perspective on the sweeping changes American culture has seen in the last few decades. Russo wasn't an instigator at the Stonewall uprising of 1969, but he immersed himself in gay-rights issues soon after, becoming a prominent voice on the New York scene. In a clip early in the film he makes clear what separated him from generations of gay people before him. "I don't know what was different about the way I was raised or the way I reacted," he says, "but I never once, not for a second, believed that it was wrong to be gay, that it was a sin, that homosexuality was evil." And he wasn't interested in being quiet or being in some closet. "He was fully equipped with ideas and arguments, and he was ready to take you on," David Ehrenstein, a writer and fellow member of the Gay Activists Alliance, recalls in the film. Russo's version of gay liberation wasn't one that mainstream America could endorse, then or now, but it was of course a pre-AIDS view. "Vito loved sex," Michael Schiavi, author of a biography about him, says. And Vito was of a generation when having sex with as many men as you possibly could was a way of expressing gay pride. His intelligence and fearlessness put him at the center of the gay-rights movement, but he was also busy establishing himself as a television host and a film scholar, creating a popular lecture in which he showed how surprisingly open movies before Hollywood's Production Code were about homosexuality and then how gay people were subtly demonized in the films that came after. The work became the book "The Celluloid Closet." Mr. Schwarz's film is nothing fancy - the usual mix of historical images and interviews with acquaintances and experts - and Russo, perhaps, was not so different from other gay activists who were silenced by AIDS. But the smooth telling of Russo's story juxtaposed against the present day, when gay marriage is sanctioned in some states and gay characters are all over prime-time television, drives home how different the cultural landscape is from the one Russo knew. Russo, though, seems like a man who wouldn't have spent much time savoring the changes. Not with all the discrimination and homophobia that remain. Vito HBO, Monday night at 9, Eastern and Pacific times; 8, Central time. Directed by Jeffrey Schwarz; Bryan Singer, executive producer; Mr. Schwarz, producer; Philip Harrison and Lotti Pharriss Knowles, co-producers; Mr. Harrison, editor; David Quantic, director of photography; Miriam Cutler, composer. For HBO: Sheila Nevins, executive producer; John Hoffman, supervising producer.