Eliot Ness spent his last years in Coudersport, Pennsylvania, telling skeptical bar patrons that he was the man who took down Al Capone. The truth was more complicated than either his boasts or the movies. Born in Chicago in 1903 to Norwegian immigrants, he studied political science and business administration, ran credit checks for the Retail Credit Company, and absorbed the scientific policing ideas of Berkeley police chief August Vollmer. At 27 he was picked by U.S. Attorney George E.Q. Johnson to lead a small squad against Capone’s breweries, choosing his men by auditing personnel files for anyone who could not be bought.

This episode separates the legend from the record. The raids that began in March 1931 bled Capone’s cash, but it was the IRS tax case that sent him to prison for 11 years. It then follows Ness to Cleveland, where as safety director from December 1935 he modernized the police before the torso murders in Kingsbury Run exposed the limits of his methods. Divorces, heavy drinking, a 1942 drunk driving cover-up, a failed 1947 run for mayor, and a string of bad business ventures followed. He died of a heart attack on May 16, 1957, at 54, just after approving the galleys of The Untouchables.

• Ness’s squad used wiretaps to map yeast deliveries and barrel movements, destroying an estimated $500,000 in bootlegging operations within six months.
• Capone’s men offered him $2,000 a week to look away. His refusal led Chicago Daily News reporter Charles Schwarz to coin the name the Untouchables.
• Ness and Capone met in person only once, in May of 1932, when Ness helped escort him from the Cook County Jail to the train bound for the Atlanta penitentiary.
• In Cleveland he personally questioned suspect Dr. Francis E. Sweeney with a polygraph, then ordered the Kingsbury Run shantytowns evacuated and burned, a move that wrecked his reputation as a reformer.
• The memoir written with Oscar Fraley sold 1.5 million copies and inspired the 1959 television series and the 1987 film. A 2014 proposal to name the ATF headquarters for him failed, though its main atrium bears his name.