Portnoy’s Old Man : PATRIMONY; A True Story <i> By Philip Roth (Simon & Schuster: $19.95; 238 pp.)</i>

One of the many pleasures of Philip Roth’s fiction is his obsessive, bravura high-wire act over the line that separates history from invention. He resolutely insists on the self-sufficiency of what he has imagined, poking fun at readers who identify him with his characters, even as he invites that odious identification by creating in Nathan Zuckerman, protagonist of his last six novels, a figure who shares much of what we know about Roth’s background: his precocious Newark boyhood; his early critical acclaim as a writer of short stories; his wild popular success and unwelcome celebrity as author of a novel that sounds very much like “Portnoy’s Complaint,” for which, like Roth, Zuckerman is subjected to attacks by just about everyone.

Roth’s purpose in all this is not merely playful or cantankerous; what he means to do, and does, is make the strongest possible case for fiction’s autonomy by suggesting and then repudiating its connection with “the facts.” It’s a nervy, sometimes hilarious, now and then exasperating performance; his road of excess doesn’t always lead to the palace of wisdom. But it often does.

Mindful of Roth’s gamesome way with questions of fiction and historicity, I found myself bracing a little at the subtitle of his new book, “Patrimony: A True Story.” A true story. Was this a nickel on a string, to be jerked back at the last moment, leaving me earnest and outsmarted?

Not at all. This book--one of Roth’s very best--takes as its subject what, in time, we all come to recognize as the “real world”--the world of hospital corridors and CAT scans and second opinions, of proud men and women made helpless as babies, of loving families undergoing the terrible, inexorable subtractions of mortality. It is about the world we enter when our parents begin to die.

Roth lost his mother, Bessie, to a heart attack in 1981. Sudden, unexpected (she was in a restaurant; her last words, “I don’t want this soup”), her death was a staggering blow to her husband and children, but in the light of what happens in this book it comes to seem almost a mercy, something almost to hope for oneself.

“Patrimony” begins in 1988, with Herman Roth, the author’s father, being stricken with paralysis on one side of his face. “What had looked like him the day before now looked like nobody--the lower lid of the bad eye bagged downward, revealing the lid’s inner lining, the cheek on that side had gone slack and lifeless as though beneath the bone had been filleted, and his lips were no longer straight but drawn down diagonally across his face.”

Our parents’ faces are sacred to us, but here, as elsewhere, Roth subdues his shock and grief by translating them into meticulous observation of what is hardest to observe: the pain and dissolution of someone we love, and are powerless to save. Not for nothing the Roth family motto: You must not forget anything.

Herman Roth was diagnosed as having Bell’s Palsy. This diagnosis proved false. A brain tumor was pressing against his facial nerve, and would soon begin to affect his ability to swallow, walk and breathe. Two surgeons were consulted; each had a different procedure in mind, but they agreed on one thing: The operation would be long, dangerous and possibly ineffectual. It might even leave him in worse condition. Herman Roth was then 86 years old. When the preliminary biopsy almost finished him off, he decided to forgo surgery and let things take their course. The course things took makes for some pretty hard reading. As Roth says: “Dying is work and he was a worker. Dying is horrible and my father was dying.”

This is not a hagiography. Herman Roth was a difficult man, driven, opinionated, intolerant, a champion nag; he harried his wife to the point of considering divorce, and when she died he lavished his fault-finding talent on his sons and grandsons and especially on Lil, his lady friend:

“I know how to open a can of soup,” she said.

“But you’re not holding it right.”

“Herman, let me be. I am holding it right.”

“Why can’t you just do what I ask you when I ask you? It isn’t right. Hold it from the bottom .”

But he also was a good man, fiercely loyal, affectionate, devoted to his family and his community, of which he became an unofficial, compulsive historian. Name an address in Newark and he’d tell you who lived there, and who the neighbors were--all the neighbors. He’d tell you even if you didn’t ask. He couldn’t help himself. Herman Roth regarded his memory as a gift too marvelous to keep to himself. He bestowed it on the world, like his nagging, as a sign of his love.

He also was a fighter. He fought his way to conspicuous success at Metropolitan Life, a company not remarkable for its hospitality to Jews. When in his old age he got mugged, he demanded his empty wallet back, scolded the mugger, and admonished him not to spend his booty “on crap.” In argument he wouldn’t give an inch.

This stubborn, combative spirit, which suited him well for “the obstacle course nearly everything had been,” did not always suit him well for the role of a father. It is a measure of the author’s growing respect for him in his last days that he came to cherish the same qualities by which he had felt oppressed as a boy. He cherished them both as a son and as a novelist; Herman Roth is one of the most vivid, powerful characters in the Philip Roth canon. And he’s got some of the best lines: “Even the bastards die. . . . That’s about the only good thing you can say for death--it gets the sons of bitches, too.”

Roth stuck with his father throughout his progress toward death. He was witness to Herman Roth’s suffering, his courage, and his decline to helplessness. It was, paradoxically, in his helplessness that the two men came to know each other most profoundly; when Philip Roth became father to his father, and Herman Roth son to his son. This splendid book is the author’s true patrimony, both his reward and ours.