Tough Guys in Sin City : THE DEATH OF FRANK SINATRA.<i> By Michael Ventura (Henry Holt: $22.50, 305 pp.)</i>

No one has ever written the Great Las Vegas Novel. What possible fiction, after all, could surpass the reality of a city built by gangsters, administered by Mormons and run without clocks? Even noble literary attempts have fallen short: the most tragically poignant tale surrounding John O’Brien’s “Leaving Las Vegas” isn’t found in the novel’s fashionably nihilistic plot, but in the knowledge that the young author killed himself days after selling his book to the movies.

Las Vegas fiction was long ago abandoned to the sensibilities of pulpsters like Mario Puzo. Meanwhile, the best prose on the Nevada Gomorrah has come from nonfiction fabulists like Tom Wolfe and Hunter Thompson, whose early assaults on Las Vegas still rank as some of the best work of their careers.

With Wolfe’s 1964 Esquire piece “Las Vegas (What?) Las Vegas (Can’t hear you! Too noisy) Las Vegas!!!!” he almost single-handedly midwifed the New Journalism; with “Fear and Loathing in Las Vegas,” Thompson showed that the most hallucinatory desert nightmares are best based in truth. The roll call of reporters who have taken memorable literary whacks at the town is deep: from A. J. Liebling to Joan Didion, Las Vegas is the town that seemingly no good memoirist could ignore.

Among the very best of these true-life Las Vegas chronicles is a lengthy 1990 article written by Michael Ventura for the L.A. Weekly. Entitled “Las Vegas: The Odds on Anything,” the piece is a collision of wit, personal confession, armchair sociology and revisionist history. “We loved Vegas because we knew the house rules, which are as follows,” Ventura wrote. “As long as you don’t bother the other customers, you can do anything.”

Now, Ventura has upped the ante by taking his visions fictional in his new novel “The Death of Frank Sinatra.” Wrapped around the tortured world of protagonist Mike Rose, a Strip-side private eye tap-dancing on both sides of the law, Ventura’s Las Vegas is not really a city, but a metastasizing malignancy killing everything it touches.

Rose, ne Rosselini, comes to his Vegas with a birthright. The locally born son of a chorus girl and low-level mobster who met when Bugsy Siegel was still breathing, Rose has memorized all the rules. “Scared money never wins,” he reminds himself in one of his many inner monologues. “One of the tougher lessons is: You can’t fight luck,” he goes on. “There are no innocent bystanders in Vegas,” he intones, “Nobody comes to Las Vegas to be innocent.”

As thoughtful as Philip Marlowe and as cynical as Sam Spade, Rose is a walking history of all that has gone down in Sin City. Still, he has his own code of hard-boiled innocence. “Because in the dirtiest business in the dirtiest town of all, I didn’t do the dirtiest thing,” he says, “not love, not even money, just killing.”

Rose’s tough guy lectures on sin fall short, however, as he is trapped by his supporting characters into just the kind of mayhem he has renounced. The nightmare begins when his schizophrenic brother, Alvi, just released from the mental hospital, mouths off to Zig, an ancient gangster who long ago killed Rose’s father and slept with his mother. Throw in a gallery of mobsters in desperate pursuit of the detective, a devilish client who wants Rose to murder her husband and a beatific former prostitute now running a New Age church in the desert, and one has a Vegas scenario, as Ventura wrote six years ago, where one “can do anything.”

In fiction, however, one can’t. And in “The Death of Frank Sinatra,” Ventura translates his Vegas apocalypse into a work that can be simply described as too much. Admirably, he reaches high in describing the tortured world of Mike Rose. But there is just too much plot and civic history, too many bloated characters and descriptions of murder via meat hook to keep the novel from toppling over from sheer exhaustion.

The problem can be found in one inner monologue where Rose tries to make sense of the grandiose people running circles around his memory: “So Joy slept with Sinatra,” Ventura writes, “and Mama slept with Sinatra. And Joy slept with Kennedy, in those days when he was haunting Vegas with Sinatra’s crowd. And Zig was approached to hit Kennedy. And Pop helped Zig whack some of the shooters who got Kennedy. And Joy slept with Giancana and Elvis . . . . I guess it’s history of a kind.”

Whew! And Sinatra doesn’t even die! By trying to make his novel a Las Vegas version of “Day of the Locust,” Ventura overshoots his mark. Nathanael West was able to capture the horror of Los Angeles with small, desperate characters aiming for salvation. In “The Death of Frank Sinatra,” Ventura starts with exaggerated monsters headed directly for the apocalypse.

Still, in mixing the detective and literary genres, Ventura bestows many readable treats. With a smaller canvas where he aims for less plot and more characterization, he may yet write his masterpiece of a novel. Until then, however, readers will have to make do with the fact that in Las Vegas, truth seems stranger--and more moving--than fiction.