PLAY IT AS IT LAYS follows Maria Wyeth, an occasional actress and part-time wife of director Carter Lang, on her descent into herself and her surroundings. When Maria (long "i") arrives at the bottom, the finds nothing, but by then who cares? Certainly not she. Based on Joan Didion's same-titled novel, this is a Hollywood film about Hollywood people. Most of them have knowingly ugly souls; all of them are unhappy. Ambition motors them through their non-lives, and a fondly cultivated sense of insouciance cushions the ride. If Los Angeles ever was Paradise, it's lost now without the least hope of redemption. Skidding into Hell isn't a particularly new theme, but Maria rolls in with a nihilistic style all he own. The film is a generally successful, often beautiful, always depressing account of her journey.

Maria shares her empty despair with B.Z., her husband's producer, her homosexual friend who has grown weary of giving everyone favors. Ostensibly amused by L.A. playing itself, he is more alienated than Maria. His father visited Lourdes and lost his faith; B.Z. didn't bother with the trip. He sits at the bottom of the well which Maria is falling down. All he can do is smile and welcome a companion. They share the parties and friends, and make the right cynical jokes. And they both know that it adds up to zero.

The movie people are as unreal as their medium makes them. Carter makes his reputation by callously digging into Maria's past and releasing her photographed emotions as his first film. A talk-show panelist calls it "an existential performance." (It couldn't be Maria's life anymore.) But the manipulation goes deeper. A woman watching T.V. footage of her house sliding into the ocean comments on the good camerawork. Early in the movie while the camera pass the desert and finally settles on a God-forsaken huddle of buildings. Maria's voice-over tells us that she grew up in a nearly deserted town called Silver Wells, Nevada. Maria says, "This is not Silver Wells."

JOAN DIDION'S SCREENPLAY transfers many of her book's best elements to the film. Besides emphasizing the film's first-person point of view, Maria's soundtrack commentary fills in gaps where dramatization would only waste time. In the book Maria talked about Carter's first films; here we see and use them to piece together her past. Her descriptions of her mentally disturbed daughter, Kate, find visual equivalents in her visits to the institution where Carter has committed their daughter. On the other hand, with the fast-cut flashbacks to Maria's coerced abortion, the style distracts us from her horror. The book played L.A.'s bleakness against the desert's, and the film tries some of the same tricks. The people have migrated media well, the geography much less so.

Unfortunately, the freeway scenes don't work, and that is mostly director Frank Perry's fault. Didion evoked a city covered in concrete, highways going from nowhere to nowhere. Perhaps filming that inner vision is doomed to fail, since once we see the traffice, it's too familiar to be as arid as Didion's prose images. Still, Perry's attempts to imitate her taunt staccato sentences with abrupt cutting and flashes to yield signs (symbols, anyone?) just doesn't catch the throbbing pulse of Maria's driving--her personal substitute for suicide. When the action moves out to Carter's shooting location in the desert. Hell is still other people, but Perry successfully concentrates on them, and not on the plastic city they have built.

If Perry's editing is dubious, the performances from Tuesday Weld as Maria and Anthony Perkins as B.Z. are unquestionably fine. Ms. Weld plays Maria as if she, too, had once had all the acts and didn't know what the game was. Her Maria is resigned, not fragile, passive instead of weak. She quietly conveys Maria's estrangement, too weary to be desperate, which makes her response that "nothing applies" the only logical conclusion. Perkins comes on a bit too affably at first, but he successfully converts his tremulous smile--which he has undoubtedly copyrighted--from amusement to sadness to despair. The two build a completely believable sense of understanding between their characters. When B.Z. gives up and takes an overdose of Seconal in front of Maria, she knows better than to try to dissuade him. In the saddest, most human moment of the film, she holds him and sings to him as he waits for death.

MARIA'S LOS ANGELES is a place empty of love, devoid of pleasure. Her citizens get through on one-night stands, supported by drugs, casually chancing another combination when the parts never did fit together. Maria's people don't make love, they fuck. They don't enjoy that very much either. Maria and B.Z. share the tenderness of fellow travellers, but it dies there. It's a mechanized automatic world whose chief symbol is the car. "Not many children around?" Maria asks a motel housekeeper. "I used to have one," the woman replies. "She totalled my Chevy."

Maria tells her story from the institution where Carter has committed her. She must be insane, didn't she let B.Z. die? But looking from Maria's angle it's peculiar she didn't join him. She's had an abortion Carter blackmailed her into. Kate, the only person she loves, is locked away. Maria and company are out of hope, and ambition is a lousy substitute for feelings. Maria's are numb, anyway. She goes on out of habit. When, finally, nothing matters, the B.Z.'s ask why stay alive. The Maria Wyeths answer, "Why not?"