By the end of Brian DePalma's 1987 film, "The Untouchables," naive Prohibition agent Eliot Ness evolved into an iron-willed Enforcer, destroying Scarface Al Capone's booze-peddling, bat-swinging reign of terror by thwarting smugglers while galloping horseback along Canada's border, saving an imperiled baby stroller from tumbling down Union Station's steps, tossing Frank Nitti off a courthouse roof and finally outwitting Capone himself during the gangster's tax-evasion trial. As police cart Scarface off to jail, the triumphant Ness (played by an eager, Armani-clad Kevin Costner) cries out to him, "Never stop fighting till the fight is done."Thus another generation was introduced to Ness' band of intrepid Untouchables; younger moviegoers cheered alongside others who remembered Robert Stack's granite-jawed portrayal of Ness in the 1960s TV show that inspired the movie. But although screenwriter David Mamet's script and the plots in Stack's show are obviously overblown and fanciful, the idea of Ness toppling Public Enemy No. One is generally accepted, primarily because no one has actively set out to dispel what experts know to be largely myth. And that's precisely where journalist Paul Heimel wishes to come in. Heimel's self-published "Eliot Ness: The Real Story" is touted as the first complete biography of the crime fighter's life and looks to expose the fraudulence of the Ness legend."His accomplishments in Chicago were somewhat significant, though not what they were made out to be," says Heimel. "He never brought down Al Capone; the government, particularly IRS agents, were mostly responsible for putting him in jail. I certainly came to the conclusion that it wasn't the blood-and-guts, Ness-versus-Capone story. He did crash into some breweries and smashed up some bootlegging equipment, but he wasn't like Stack or Costner or anything like that."Heimel asserts that most biographers avoided writing about Ness because "the real story" was simply too dull. "I think that anyone who may have pondered or attempted researching the story probably concluded that it wasn't nearly as exciting as they felt it would be when they began researching," he explains. "I think they also fought an uphill battle trying to put the truth in front of the public when the legend has so much more appeal."Heimel seems to be engaged in a similar fight. He first became interested in Ness while growing up in Coudersport, Pennsylvania, where Ness died. More than three years of research has produced a book soundly wrecking the image of a dapper, dramatic, Tommy-gun toting Ness; instead, the man traditionally considered the model for Chester Gould's cartoon hero Dick Tracy is portrayed as a troubled, womanizing alcoholic whose main claim to fame was cleaning up Cleveland police corruption when serving as the city's public safety director. As a result, he says, publishers were reticent to buy the manuscript."I was caught between writing a scholarly book, which would have to be extensively footnoted and textbook-like, and a mass-market paperback, which I was told would have to be embellished with fictional dialogue involving his marriages and police cleanup," he says. "I refused to do either, and so had to put it out myself."Still, Heimel manages to bring some color to Ness' story, particularly his early life in Chicago. Heimel was also a chief consultant on an A&E Network "Biography" profile on Ness that airs January 22. His book has received attention in Cleveland, where he will appear at an upcoming book signing, and in Germany, where apparently there is high demand for any tales connected to American gangsters. But Heimel has yet to find distributors in Ness' hometown of Chicago, which has been seemingly uninterested in a stripped-down account of the Federal agent. (Ness buffs can order the bio for $12.95 from Knox Books, 407 Mill Street, Coudersport, PA 16915.) Ironically, most of the book's more interesting nuggets are found in Ness' early years in the Kensington neighborhood, where his Norwegian father owned several South Side bakeries. The young Ness was quiet and studious, but eventually attracted a gaggle of female admirers. He pledged Sigma Alpha Epsilon fraternity while attending the University of Chicago and practiced martial arts in his spare time. Soon after graduation, he found himself working for the Justice and Treasury departments as a Prohibition agent. Although Ness was obsessed with Capone, refused bribes and was rather successful (and moderately publicized) when cracking down on several illicit bootlegging operations, he wasn't a factor in the government's tax-evasion case against Capone.By the time Heimel began his research, he could find only two living witnesses of Ness' activities in the 1930s, including a since-deceased member of the Untouchables crew. Much of Heimel's information came from Capone biographies and newspaper clippings. He was also thwarted by Ness' own exaggerations. The agent's Depression-era exploits were mostly forgotten until the late fifties, when a broken and debt-ridden Ness co-authored an autobiography, "The Untouchables," with sportswriter Oscar Fraley. Fraley apparently took significant liberties with Ness' originally dry story, but Ness approved the galley proofs anyway, partly because he was desperate for money. "His little lie, his consent to have that published really took on a life of its own so that it really obscured all of his legitimate accomplishments," says Heimel. Those accomplishments came in Cleveland, where Ness was appointed public safety director after FBI chief J. Edgar Hoover thwarted Ness' dream of becoming a G-man (chiefly because Hoover despised the agent who wrote Ness' recommendation). "In Cleveland it's incredible what Ness did in terms of cleaning up the city," says Heimel. "The police force was a joke, completely corrupt; fire protection was poor; and it was one of the deadliest cities in the country in terms of traffic safety. He cleaned all that up."After a drunk Ness was involved in a hit-and-run accident, though, he resigned his post and went to work for the government's Social Protection Program in a bizarre attempt to eliminate the transmission of venereal disease. After losing by a landslide in Cleveland's 1948 mayoral election, Ness stumbled through a string of failed marriages and businesses before dying in Coudersport at the age of 54.Some shreds of Ness' life story have accurately appeared in Capone biographies, most notably in Laurence Bergreen's "Capone: The Man and the Era." But even as Heimel markets his book as the definitive Ness bio, he openly acknowledges the difficulty-and possible futility-of toppling Ness' legend with a decidedly duller reality. "To be honest with you, I think the search for the truth will probably fade away," he says. "The 'Biography' episode is informative and sad, but not one of the most dramatic ones the series has aired. Candidly speaking, I think the myth is too big to shake."