In "This So-Called Disaster," Michael Almereyda's peek behind the theatrical curtain, actors thunder and rage, pushing themselves in the name of art and demons we can barely imagine. In one corner of a shadowy stage, Nick Nolte thunders like Zeus on a bender; in another, Sean Penn glowers with squinting mean eyes while Woody Harrelson nervously goes through his paces. The occasion for all this male volcanic tumult, this spew and these howls, are rehearsals for Sam Shepard's "The Late Henry Moss," an autobiographical, coruscating drama about the playwright's relationship with his dead boozer father.

The last time Almereyda worked with Shepard another dead father was looming over the two men — the late King of Denmark, who Shepard played in Almereyda's criminally and vastly under-appreciated screen version of "Hamlet" (2000). Wearing a long coat and shimmering in and out of scenes like a mirage, the author of such seminal American plays as "Curse of the Starving Class," "Buried Child" and "True West" played the murdered King with potent cowboy cool — part Gary Cooper pinup, part punk-rock god. Unsurprisingly, given his iconic appearances in filmslike "Days of Heaven" and "The Right Stuff," that's more or less how heinitially comes across in "This So-Called Disaster," which Almereyda shot in 2000 during rehearsals for its premiere at San Francisco's Magic Theatre at Theatre on the Square.

Almereyda claims he was given complete freedom to shoot the actors while they were in the theater, and whether or not that's precisely true what he's managed to capture with his digital video camera makes for surprisingly compelling viewing. (Having not been transferred to film, the piece will be shown in projected video.) Beautifully shot and cannily assembled, most of the material involves the actual rehearsals, but there are also talking-head interviews with Shepard — alone and with select cast and crew — interspersed with what look like old home-movie footage, some black-and-white still photographs and bits of the play's text printed on title cards. You never see or hear Almereyda, but you can feel his keenly interested presence, his vision and intention, in each darting camera move and edit, even in the shockingly close shot of an actor's blinking eye.

However unfettered Almereyda's access, he spends little time rooting around in Shepard's history. Rather he gives us palpable sense of the playwright through his gestures of work, his interactions with the actors and snatches of off-stage conversation.

The view of the actors is more fleeting though comparably rich, with Penn and Nolte the obvious main attractions. By turns tender and brutal, Nolte comes across as a man who's torn down every barrier between him and the world — he's a mesmerizing, poignantly naked slab of humanity. Penn registers as far more guarded, wary as a caged cat, and there's a sense that no matter how deep he digs he will always withhold a piece of himself. Withone actor, you see a consciousness eagerto transcend itself; with another, yousee an actor who adamantly refuses to let go.

In its vision of the push-and-pull of rehearsal and the revelation of how a play comes to breathing, snorting life onstage, Almereyda's video brings us close to the act of creation. The limitations of "This So-Called Disaster" — the phrase is how Shepard's father once described to his son his marriage — ironically turn out also to be its greatest strengths. Foregoing the usual biographical details and events, the kind of yawningly familiar back-story of adversity and triumph, Almereyda instead brings us intimately into the creative process. As Shepard builds his production moment by moment, gesture by gesture, he is also necessarily breaking it down so that his actors can absorb its pieces, digest its meaning in order to build it up again onstage. The beauty of "This So-Called Disaster" is that it lets us ride shotgun in this journey, with one eye on the driver and the other fixed on the road.

'This So-Called Disaster'

MPAA rating: Unrated

Times guidelines: Intense emotional exchanges, some language

Sam Shepard...Himself

Nick Nolte...Himself

Sean Penn...Himself

James Gammon...Himself

Cheech Marin...Himself

A Keep Your Head Up production, released by IFC Films. Director Michael Almereyda. Producers Callum Greene, Anthony Katagas. Executive producers Jonathan Sehring, Caroline Kaplan, Holly Becker, John Sloss. Camera Andy Black, Adam Keker, Amber Lasciak, Michael McDonough. Editor Kate Williams. Running time: 1 hour, 27 minutes. Exclusively at Laemmle's Monica 4-Plex, 1332 2nd St., Santa Monica, (310) 394-9741.