MR. CAPONE By Robert J. Schoenberg Morrow. 480 pp. $23

TO SAY that Al Capone was evil incarnate seems no particular exaggeration of the truth. He was a squat, cretinous creature who looked out at the world through little pig eyes, a murderous man to whom human life seems to have been utterly inconsequential and valueless. During the 1920s he became the personification of organized crime in America, a distinction he retains nearly a half-century after his death from -- there may indeed be a just God -- syphilis. "His name is still recognized everywhere," Robert J. Schoenberg writes, "without any explanation needed about who he was or what he stands for . . ."

Since first coming to public attention during the Chicago gang wars of the Prohibition era, Capone has been both vilified and lionized. The violence he so casually dispensed has been deplored and romanticized in approximately equal measures; for every newspaper editorial or work of history lamenting his deleterious influence on American life, there is a motion picture or work of fiction glamorizing the "Scarface" legend. He is -- there can be no getting around it -- an American icon, though what this says about America is still a moot point among those who attempt to plumb the nation's psyche.

Schoenberg is less interested in the larger meaning of Capone's life than in its minutiae. His biography -- the first substantial one since John Kobler's excellent Capone, published in 1971 -- focuses not on Capone as folk hero but on Capone as underworld entrepreneur. Though he cannot avoid the messy and inconvenient matter of murder and other forms of enforcement, Schoenberg focuses on Capone as "a businessman of crime {who} had lucid, rational and discoverable reasons for his actions," a man who believed that "the proper business of crime was business."

In this interpretation of Capone's career Schoenberg stands precisely opposed to Robert Lacey, whose recent biography of Meyer Lansky made a persuasive case that organized crime is notable primarily for its disorganization. Though Schoenberg certainly shows that crime made Capone immensely powerful and rich, at least for a time, most of the evidence he presents tends to confirm Lacey's theory rather than his own. What he depicts is not a "business" but a chaotic house of cards held together by bribery and intimidation, one that was bound to collapse -- or go further underground -- under the weight of the law, however belatedly and erratically that weight was applied.

Perhaps Schoenberg's interpretation would be more convincing if Capone had attempted to channel his gains into legitimate enterprises; this laundering process, after all, was employed by many men whose names now stand as demigods of American capitalism. But Capone never made this transition because he was a thug to the core, incapable by reason of both instinct and training to imagine anything for himself except the criminal life; the concessions he occasionally made to convention -- his expensive suits, his estate in Miami -- were merely gangster garish.

The story of his life is well known in outline, but Schoenberg fleshes it out with layer upon layer of detail. Though some of this eventually becomes merely repetitious and exhausting -- Who killed whom? dissolves into Who cares? -- much of it is interesting and revealing. Schoenberg's cast of characters is immense, embracing as it does not merely the vast universe of 1920s and '30s crime but also an astonishing panoply of elected and appointed law officers who eagerly collaborated with Capone and his toadies.

He was born in New York in 1899, moved to Chicago in 1919. Precisely how his career there began is unclear -- Schoenberg thinks that "he may have started as a bouncer at the Four Deuces at $35 a week" -- but his rise was rapid: "Chicago and Al Capone made a perfect marriage," for, as a local alderman of the day put it, "Chicago is unique. It is the only completely corrupt city in America." With Prohibition now taking effect, the opportunities for corruption grew exponentially.

Capone seized as many of them as he could. But though he soon became "the Big Fella" in Chicago, he had to spend an inordinate amount of time dealing with rivals, among them Dion O'Banion and Bugs Moran. For a while the gangsters allied in a "combine," but it proved considerably shakier than the great industrial trusts of which it was a parodic miniature. By the early 1920s gang wars were being fought all over the streets of Chicago; the chief implement of destruction was the newly minted Thompson submachine gun, aka the Tommy gun, which reached its spectacular apotheosis in the St. Valentine's Day Massacre of 1929 and ultimately claimed most of the more than 700 lives snuffed out during this homicidal orgy.

That was the beginning of Capone's end. Gang violence wasn't amusing any more. Though most local law-enforcement officers remained in Capone's pocket, federal ones at last began to move. It took a while, as such matters so often do, but in 1931 the feds nailed him on tax-evasion charges and put him in the Atlanta penitentiary; soon they moved him to Alcatraz, cutting the last of his ties to his "organization" and leaving him with little to do save live out the remaining decade and a half of his life. He was released in the fall of 1939, by which time the syphilis had thoroughly established itself; he drifted in and out of lucidity and eventually, in one physician's words, was "rendered pitiable," though it is difficult to imagine that much pity was wasted on him.

That this most celebrated of gangsters was brought down by income-tax charges of dubious validity is, as has elsewhere been remarked, both an irony and a mockery of justice. Nowhere in the story of Al Capone can one find anything ennobling or inspiriting; incapable of convicting or even indicting him for the gross offenses he had committed, the law got Capone on a trivial charge that may not at the time have had legal standing. However relieved most Americans may have been to see him packed off to prison, they also knew that only a technicality stood between him and business as usual. This is yet another reason why the nation emerged from Prohibition with its respect for the law so grievously diminished.