Old Man Ripper : THE WOMEN OF WHITECHAPEL AND JACK THE RIPPER, <i> By Paul West (Random House: $22; 404 pp.)</i>

Real murderers’ minds are black holes that emit no light. The thousand pages of Norman Mailer’s “The Executioner’s Song” dwindle to the unanswered question of why Gary Gilmore shot two of the people he robbed. The last half of Truman Capote’s “In Cold Blood” collapses because the drifters who massacred a Kansas family are unequal to their crime. Serial killers--Jack the Ripper, for instance--fascinate us, but the inside of a serial killer’s head may be the least interesting place a journalist would want to explore.

But what about fictional murderers? The Ripper, who carved up several London prostitutes a century ago, has never been positively identified. Couldn’t a novelist--say, Paul West, who already has played with the past in such works as “Lord Byron’s Doctor” and “Rat Man of Paris”--make him anything he chose?

“Although I based this novel on facts,” West notes, “I based it on few enough of them. . . . Each (Ripper historian) denounces the others’ work as ballyhoo, which is the ideal starting point for a true merchant of the untrue.”

West’s Ripper is not that longtime suspect, Prince Albert Victor Christian Edward, Queen Victoria’s grandson. In this novel, “Eddy” is an amiable dimwit, introduced to bohemian society in the East End by Impressionist painter Walter Sickert. One of Sickert’s slum models, Annie Crook, has a daughter by Eddy. The child is 3 years old when the prime minister, Lord Salisbury, acts to remove what he sees, in an age of socialist agitation, to be a threat to the monarchy.

The dirty work is done by Sir William Gull, physician in ordinary to the queen and “the most famous vivisectionist of his day.” The child is kidnapped. The mother receives a frontal lobotomy and is confined to Gull’s “Pudding Club,” a dank hospital basement where she and other lobotomized women eat potato peelings, sleep on stone benches and slowly lose their humanity: “an experiment in fusion.”

When four prostitutes write to the queen, inquiring about Crook, offering to care for the child and asking for money, the prime minister is furious. “Make certain they understand, “ he tells Gull. “There is not a natural conduit from the lower orders to the Throne, certainly not on such matters as these. Put paid to them, sir.”

Gull takes these vague instructions to heart. Between August and November, 1888, he and his coachman, Netley, kill all four signers of the letter, plus a fifth woman by mistake. The victims are lured into a coach ironically called the “Crusader,” drugged and mutilated according to the “Masonic manual of ritual murder” so that the cabal of Freemasons that runs the country (including Salisbury and the commissioner of police) will know that its wishes are being carried out.

As fictional murderers go, West’s Gull is a juicy creation: everybody’s nightmare doctor, a “law unto himself” corrupted by absolute power. Given the novelist’s freedom, though, it’s a bit of a disappointment that the Ripper’s motivation, however tinged by madness, turns out to be simple realpolitik.

The portrait of Sickert is far more subtle. A confirmed slummer, believing that even the sleaziest experience can be transmuted into art, he gradually loses his moral bearings. Forbidden thrills, his habitual posture as a spectator, fear for the child’s life and his own--all lead him, step by step, into the horror of being Gull’s accomplice, even handing a couple of his ex-mistresses through the door of the death carriage.

Redemption, Sickert soon realizes, is impossible. Yet he goes on painting, rationalizing, hoping: “An artist--or anyone--could not love people without loving their pain; yet how could anyone in his right mind love it, even relish it? . . . The way was . . . through some prodigious empathy that made him into what he painted.”

But exactly because the fiction can be so persuasive, we sometimes find ourselves wishing West were a journalist, required to offer us evidence. Why did he pin the crimes on these particular people? Not Salisbury; prime ministers can take care of themselves. But shouldn’t Gull’s ghost sue? Shouldn’t the Masons, who rank among history’s perennial scapegoats, cry foul? Can we look at Sickert’s paintings--including those of a woman murdered 20 years after the Ripper--in quite the same way again?

Such doubts nag at us, but we can’t help reading on. West is a superb stylist. His leisurely, filigreed prose evokes both the prim surface of the Victorian era and its lecherous underside. Like the lamps of the “Crusader” picking out the gleam of knives and the swirl of fog, he illuminates grisly events and the eddies of fear, pornographic glee and media hype that surround them, equally adept at describing Sickert’s painterly way of seeing and the coarse, unsentimental, hopeless pluck of the women about to die.

We don’t, after all, read a 400-page novel about Jack the Ripper just to hear a new theory about who he was and why he killed. We read it to get an altered sense of life. This West delivers. It’s no accident that the book’s most moving scene--a scene worthy of Dickens--isn’t one of the murders but Annie Crook’s brief escape. Illiterate to begin with, her memory as tattered as her clothing, she wanders halfway across London, “jostled, laughed at . . . steered, tripped, shoved, badgered, in the end bleeding,” to find her daughter before Salisbury’s agents yank her back into captivity.

Indeed, as the title suggests--”The Women of Whitechapel” coming first--this is a feminist book. West’s aim is to resurrect not only the five victims but a host of the forgotten. The Ripper’s knife, he makes clear, is only the sharpest instrument in a vast operating theater: a society dominated by men and money. For poor women, virtually destined to walk the streets, as if in infancy their “pretty little hairless private places had on them a label that read ‘For Public Consumption’ or, worse, ‘Public Convenience,’ ” the whole world is a Pudding Club.