Sam Shepard stages a bleak parable of two families A Lie of the Mind Play by Sam Shepard. Starring James Gammon, Harvey Keitel, Geraldine Page, Will Patton, Amanda Plummer, Aidan Quinn, Ann Wedgeworth, Karen Young. Directed by Mr. Shepard.

In ``A Lie of the Mind,'' his new two-family play at the Promenade Theatre, Sam Shepard once more hears a lost America singing. The voices are off-key. The tone is dissonant. Only a certain mordant humor -- plus the welcome country-western musical interludes by the Red Clay Ramblers -- relieves the bleakness of this dark and difficult work. ``A Lie of the Mind'' lasts nearly four hours (with two intermissions). The marathon drama begins in the aftermath of violence as the lethally jealous Jake (Harvey Keitel) and his brother Frankie (Aidan Quinn) discuss the steps to be taken following Jake's brutal beating of his wife, Beth (Amanda Plummer). Jake believes he has killed her. Beth has been rescued by her brother, Mike (Will Patton), and hospitalized, but has suffered brain damage from which she never fully recovers.

From this point on, ``A Lie of the Mind'' shifts back and forth between the California domicile presided over by Jake's widowed mother, Lorraine (Geraldine Page), and the Montana household headed by Baylor (James Gammon), Beth's totally insensitive father. When Frankie visits Baylor's family to discover whether or not Beth's beating has proved fatal, he is wounded by a rifle shot from Baylor and taken guest-prisoner. He is also plunged into a nightmare world from which there is no escape. Jake ultimatel y turns up clad in his father's bemedaled Air Force field jacket and draped with a huge American flag. His arrival leads to the final symbolic actions of this tortuous parable.

As is not uncommon with Shepard plays, women fare poorly in ``A Lie of the Mind.'' Beth is battered. Lorraine was deserted by her alcoholic husband. Pitiful, mentally frail Meg (Ann Wedgeworth) is demeaned by the obtuse Baylor. Frankie introduces the only note of rationality into this irrational world.

``A Lie of the Mind'' also reflects what has come to be known as Mr. Shepard's mythic quality. The title connotes the characters' self-delusion and self-deception as well as the mind-set at the heart of their obsessive, elemental behavior, notably on the part of Jake and of Beth's vengeful brother, Mike. There are times when ``A Lie of the Mind'' seems rather like a 1980s ``Tobacco Road.''

Shepard seeks to enlarge the play's perspectives with comparisons between America's now and then. When Lorraine's daughter Sally (Karen Young) talks of hitting the road and wonders where she will go, Lorraine assures her that there are towns all over, ``and if you don't find one, start one.'' Replies Sally: ``That was another time.'' And when Meg diffidently points out that, unlike the pioneers, Americans no longer need hunt animals to feed themselves, Baylor replies: ``Hunting is no hobby. It's an art . . . . You hunt deer in season. That's what you do.'' The National Rifle Association couldn't have put it more succinctly.

While Mr. Shepard maroons Frankie with the afflicted Beth and her family, his mother and sister are flying to Ireland in search of family roots -- but not before Lorraine sets the family home afire. No one can accuse Shepard of not trying to touch all possible bases.

The feel for Americana -- however bizarre -- that characteristically invests Shepard's writing also marks the consistently excellent performance the author has staged. If, in the end, the results don't fully justify the effort, it is not for want of dedication on the part of all concerned. The production has been designed by Andy Stacklin (settings), Rita Ryack (costumes), and Anne E. Militello (lighting).