Roman a Clay Feet : A HOUSE OF SECRETS <i> By Patti Davis</i> ; <i> (Birch Lane Press/Carol Publishing Group: $18.95; 240 pp.)</i>

“My whole life with my family feels like a tour through a foreign country where I don’t know the language and don’t understand the customs,” laments Carla Lawton in “A House of Secrets,” the third and latest novel by Patti Davis, Ronald and Nancy Reagan’s daughter. This affecting, earthy, impassioned book is “a work of fiction,” Davis insists in a press release, but one can reasonably surmise that many actual events inspired the story of Carla’s oppressive upbringing and subsequent alienation from her parents.

The Reagans’ painstakingly contrived public image, wholesome as a Norman Rockwell painting, already has been besmirched beyond repair by author Kitty Kelley and other writers, plus damning statements made by Davis herself. Anyone familiar with the glut of derogatory, post-Reagan-era disclosures about the former First Couple will recognize their fictional counterparts, Cliff and Rachel Lawton, affluent Californians transplanted from New York.

Genial Cliff, a high-profile financier, is an emotionally remote father to Carla and her younger sister, Lily. A decent man at heart, he childishly recoils from unpleasantness, preferring to take refuge in work and in the self-created myth of his family’s contentment.

Rachel, however, rules the Lawton household with the absolutism of a tyrant. Prudish and narcissistic, she camouflages her vicious temperament with false sweetness that dupes everybody except Carla, who says, “(My mother) can charm anyone, warm anyone’s heart. But you’d better watch your back.”

Carla ponders her dismal youth from the safe vantage point of adulthood. A California-based writer, she yearns to comprehend the past and be liberated from it, but sour memories engulf her, reawakening latent rage and frustration. In flashbacks throughout the book, we witness Carla’s early life, particularly Rachel’s warped attempts to persecute the girl.

What went on behind the closed doors of the Lawtons’ home, at least in Carla’s opinion, nearly defies belief. Again and again, she is the target of her mother’s diabolical victimization, although others--including Cliff--sympathetically see Rachel as a well-meaning parent saddled with a wayward, surly rebel who simply won’t behave.

Davis’ writing attains maximum potency when she portrays the confrontations between mother and daughter. In one bizarre episode, which occurs when Carla is 8, Rachel stomps into the bathroom, yanks the child’s clothing down and commands her to urinate right that minute.

Equally grotesque clashes follow: Rachel destroys a short story of Carla’s that depicts “locked-up children”; completely naked, she harangues the girl; and with a nylon stocking pulled down over her face, Rachel chases her terror-stricken daughter around the house. Two days later, a maid who saw this ghoulish scene gets fired.

Like young Jane Eyre, Carla survives every barrage of cruelty by nobly feigning stoicism. “Silence had become my armor,” she explains. “I hid inside it . . . I’d been found guilty of the crime of growing up, and the onslaught of my mother’s anger was my sentence.”

Rachel’s villainy does have consequences, though. Fearful of being a despicable parent herself, Carla undergoes two abortions and sterilization, which she later has reversed. Docile Lily fares badly, too. Total submissiveness exempts her from Rachel’s ire, but she privately cringes at what Carla endures. After Lily slashes her wrist in a suicide attempt, the appearance-conscious Lawtons buy her a wide gold bracelet that masks the telltale scar.

Years later, Rachel turns into a mute invalid following Cliff’s death from cancer. Lily, her mother’s vigilant care giver, dodges painful recollections by continuing to repress them. At the novel’s end, willpower, mental ruggedness and a desire to be spiritually healed combine to help Carla burst out of the “house of secrets,” a place that ravaged its other inhabitants.

Two elements significantly detract from the book’s poignancy. First, it is virtually impossible not to substitute Nancy Reagan, Ronald Reagan and Patti Davis for Rachel, Cliff and Carla. Readers will wonder what portions of the purportedly fictitious plot are true. Almost inevitably, these factors draw attention to such an extent that evaluating “A House of Secrets” as literature, rather than as a thinly disguised tell-all, becomes tricky. Davis does possess more writing talent than she has generally received credit for, talent demonstrated by the intense feelings effectively transmitted by her prose.

Even so, given the ongoing, highly publicized speculation about the Reagans’ private lives, the line between reality and invention in this book is just too murky for comfort.