Al Capone moved into union racketeering in 1920s, one of many Mafia bosses who did so. Three Capone surrogates were murdered in cold blood in the Blue Hour Saloon on April 20, 1930. A single assassin was responsible for all three deaths. The murders represented a rupture in the peace agreement in the Chicago underworld of 1930. It was also a bonafide challenge to Capone's hegemony as boss of bosses in the windy city. My e-book looks at the murder victims, how they related to Capone's union activities and his domination of Chicago city hall.