The writer returns to his theater home in San Francisco with a new chapter in his examination of fathers, sons and paranoia.

SAN FRANCISCO — Halloween Day 2000. Outside Theatre on the Square on Post Street, a woman sporting a French maid outfit trots up the sidewalk with a couple of Draculas and a faux homeless man. Nearby a genuine homeless man looks up from his fragment of bagel, muttering.

Inside, away from the sun, Sam Shepard and company are wading deep into rehearsals for "The Late Henry Moss," which opens Nov. 14. The wood-paneled hallway near the tiny, second-story box office is dark and shadowy and, Halloween-wise, a little more like it.

Lunch break. Nick Nolte, with the voice that launched a thousand gargles, eases through the door on crutches and makes his way toward the elevator. A minute later, Sean Penn, who plays Nolte's brother, whips the doors open and bounds down the stairs as if staring down invisible track hurdles. A few other rehearsal denizens file out, and then comes the playwright, who is also the director.

Five minutes later at a nearby diner, the waitress makes herself at home, plopping down on Shepard's side of the booth.

She has two questions. "You decided what you want? Who is that guy?"

"Which guy?" Shepard asks.

"The one over there."

"Jim Gammon, you mean? With the hat?" It's Shepard's longtime cohort James Gammon, a regular on the San Francisco-based television show "Nash Bridges," as is Cheech Marin. Both Marin and Gammon are in "The Late Henry Moss," along with Penn and Nolte, Woody Harrelson and Sheila Tousey.

"Very famous actor," Shepard says, smiling. "Go get his autograph."

For Shepard, who turned 57 over the weekend, "The Late Henry Moss" represents his highest-profile theatrical venture since "A Lie of the Mind" 15 years ago.

The project has brought the Illinois-born military brat back to one of his formative artistic homes. Shepard's association with the Magic Theatre launched many a Shepard premiere, from the wilds of "Angel City" (1976) and "Ianacoma" (1977) to the more straightforward and widely traveled "Buried Child" (1978), "True West" (1980) and "Fool for Love" (1983).

The geography of these works ranges from urban Los Angeles to a coma state (no jokes, now) to a Southwestern roadside motel to the farmland of Illinois. But they're all part of the same lie of the mind, the same comically desolate and bruising terrain.

"At first it was kind of shocking to be back here," Shepard says of his Magic return. "But now I feel better about it. Twenty-five years later, you know? Very strange. A lot of history. In a way it feels like you never left, and in another way it feels like you were never there." As he wrote in "True West": Time stands still when you're having fun.

Into the Past to Probe Characters' 'Father Issues'

Earlier this year in New York, a revived "True West" proved a phenomenon, with John C. Reilly and Philip Seymour Hoffman alternating in the roles of Mojave Desert rat Lee and fledgling Hollywood screenwriter Austin--brothers waging mortal combat in mom's suburban Los Angeles kitchen.

Shepard once described L.A. as a "sprawling, demented snake . . . its fanged mouth wide open, eyes blazing, paralyzed in a lunge of pure paranoia." His latest work, "The Late Henry Moss," takes place farther east, but the atmosphere's no less paranoid. In the New Mexico desert adobe home where Henry Moss (Gammon) has died, a reunion of his sons Earl (Nolte) and Ray (Penn) takes place.

Shepard's latest set of uneasy siblings is dealing with what might be called "father issues," here augmented by a neighbor (Marin), a cabby (Woody Harrelson) who saw Moss just before he died, and Moss' lover (Tousey, who appeared in the Public Theatre workshop before this full production). The old man's story, and that of his boys, unfolds by way of flashbacks, the first extensive use thereof in Shepard's career.

By contrast, this isn't Shepard's first father figure named Moss. While living in New York, Shepard wrote a 1969 one-act called "The Holy Ghostly," a standoff between a murderous "bohemian" son and his mewling, scraggly father. Years ago Shepard knew a rodeo guy "who had a cattle dog named Moss. I guess I always loved that name."

When Shepard laughs, it's surprising because his easy, well-worn, tough-guy presence seems at odds with the staccato chuckle. It's a character actor's laugh stuck inside a leading man.

Not for nothing did Shepard write a story (in the "Cruising Paradise" collection) called "The Real Gabby Hayes," which obliquely but tellingly deals with Shepard's relationship with his father.

"The Late Henry Moss" is a three-act exploration of family secrets, blood rivalry and other classic themes favored by Shepard. "It more or less directly comes from the death of my father, which was in 1983," he says. "The first peripheral stab at it was with 'A Lie of the Mind,' with the father's ashes and the folded flag." (The late father didn't actually appear.) Only now, Shepard says, was he "willing to put the corpse on stage, to actually put the corpse up there with the brothers."

He began "The Late Henry Moss" in 1989 and got an act and a half into it. "Then I just threw up my hands and said, 'I don't wanna do this.' Ran from it, in a way. Made up all kinds of excuses: that it was another rehash of 'True West,' who's gonna care? I actually sent the play to the [Shepard] archives at the University of Texas and forgot about it."

But an unfinished Shepard play tends to attract attention. Jim Houghton of New York's Signature Theatre, which devoted an entire season to Shepard's works a few years ago, got hold of it. Then others, including Shepard's friend and mentor Joe Chaikin, encouraged its completion.

"The second act," he says of the original version, "went off into all kinds of weird, tangential stuff about the Spanish conquistadors and blood and Christ, and the Sangre de Cristo mountains. It got goofy. That was part of the reason I abandoned it."

All that went in the rewrites. Shepard acknowledges the inspiration of Frank O'Connor's short story "The Late Henry Conran" regarding a narrative device used in the play.

Credit for assembling such a formidable cast must go, Shepard says, to Penn, a Marin County resident who wanted to do the play close to home. "I always wanted Sean in it," he says, "and Sean actually suggested Nick. Cheech [Marin] kinda came through through Jim [Gammon], because of 'Nash Bridges.'

"Because these actors are so extraordinary, you learn a lot about intention. You very clearly see the places the material wants to go, places you've forced it to go or pretended it should go.

"A good actor always sets you straight. If you've written a false moment and thought it was probably pretty great, the actor's gonna show you when he gets to that moment. They're the great test of the validity of the material.

"At first, I didn't want to believe that," Shepard says, with a quick chuckle. "When you're 19 and writing plays, you think every actor is full of it. They just can't handle your brilliant material."

Penn and Nolte bring nicely complementary sensibilities to a rehearsal room, Shepard says. "Sean tends to work at a slower pace; he's continually absorbing stuff but not necessarily acting on it. He likes to let it drizzle on him awhile, let it all accrue. Nick'll take leaps out there and then come back and then take another leap. Woody Harrelson's like that too.

"Cheech is absolutely incredible. Here's a man who has never done a play, but with his long career in stand-up comedy with Cheech and Chong, he's obviously learned a lot about showmanship. He's an extraordinary character actor. They say TV has a tendency to diminish actors, and I think that's probably true in the long run--it wears on 'em like bad dental work--but Cheech doesn't show any of the signs of being damaged that way. And as a man, he's fantastic."

The sold-out run of "The Late Henry Moss" is scheduled to end Dec. 17. No one has committed to a second production as yet, though New York and regional interest clearly is running high.

'A Certain Period of Grief Has to Go By'

His ham and cheese gone, Shepard wants to stress one thing: This isn't his life or his father he's dealing with, strictly speaking. It's no more directly autobiographical, he says, than J.M. Synge writing about an unruly man and his thorny father in "The Playboy of the Western World," a raucous Irish classic Shepard loves.

Nonetheless, he says, this one needed a few years' distance.

"A certain period of time has to pass, with a death that's devastating like the death of a father. A certain period of grief has to go by before you can make this other leap. And when you make that leap--not necessarily writing about it but using the event as a catalyst for something else--it's no longer strictly personal. It's no longer strictly about your own father.

"Grief is bizarre territory because there's no predicting how long it'll take to get over certain things. You just don't know how long it's going to resound in your life. Or, after it's apparently stopped resounding, when it'll come up again. It's extremely personal. That's why I could never understand this thing of grief 'counseling' or grieving 'clinics.' That doesn't make any sense to me at all. Why would you wanna be counseled in your grief? It's too private."

Emotional truth is one thing, but Shepard is just as interested these days in matters of craft. "That other stuff is always gonna be with you, the emotional earthquakes and volcanoes and all that. They're a given; they're a part of who you are. But the craftsmanship is what separates the men from the boys, the wheat from the chaff.

"The emotional [material] is there, always. But it has to have a house, a place to rattle around in. And it's not a question of neatness; it's a question of integrity. You can have the neatest house in the world, but the structural integrity has to be there, and it has to be dictated by the emotional content.

"It's not a question of building an empty house and then living in it," he says, about to venture back into rehearsals. "You have to live in it while you're building it."