It's easy to imagine the greatest American movie artists feeling that Jo March's story is theirs, too. Many of the best American movies have sprung from the pulp of westerns, science fiction, detective stories, adventure tales and horror stories. And like Jo, our filmmakers are forever trying to bridge pulp and art, trying to meld the excitement of the former with the depth of the latter.

The debate about whether movie violence causes real-life violence (an argument I've never bought) has hijacked any exploration of how violence is actually used in the movies, how audiences experience it and when violence does or doesn't qualify as art. Those are the questions that preoccupy critic Jake Horsley in his mammoth two-volume "The Blood Poets: A Cinema of Savagery 1958-1999." Horsley arrives on the scene with a combination of articulate analysis and a provocateur's punch. As with all audacious undertakings, the quality is highly variable. Over the course of nearly 1,000 pages Horsley is both thoughtful and polemical, specific and vague, rigorously logical and embarrassingly fuzzy, nobody's fool and a sucker.

But Horsley dares to place violence, and the appeal of violence, at the heart of what movies are all about. "If you're afraid of movies that excite your senses, you're afraid of movies," wrote Pauline Kael in "Fear of Movies," her great attack on squeamishness as a basis for aesthetic judgment. Horsley goes further. "My tolerance for people who flinch from screen violence, and insist that they have no time for violent movies, is accordingly extremely low. It seems to me nothing other than moral squeamishness ... Yet this weakness is, to all intents and purposes, presented to us as virtue." That may not seem very tolerant of the people who simply can't watch screen violence. But would we accord them the same sympathy if that squeamishness were used as an excuse to avoid "The Painted Bird" or "Macbeth" (or Goya or "Guernica")?

Horsley is not arguing for a blanket acceptance of any screen violence. There are certain depictions from which even he flinches. "We don't need a film to show us that violence is sordid and repulsive," Horsley writes. "We already know this." So what is the purpose of a violent film? On the surface, Horsley's answer seems depressingly familiar. "If movies can serve to bring us closer to understanding our feelings about violence," he writes, "our fear and our fascination and our loathing of it, then they have served a useful, essential purpose, a social function no less, and deserve to be tolerated, as does all art, no matter how shocking or 'immoral' they may ostensibly be."

Maya Angelou reads from "The Heart of a Woman"