The blues brought Bruce Iglauer to Chicago in 1970. A blues fan since he attended a 1966 festival performance by Mississippi Fred McDowell, Cincinnati native Iglauer founded Alligator Records in 1971 for the sole purpose of releasing one album by Hound Dog Taylor. He believed that Taylor, an obscure blues singer and slide guitarist on Chicago’s South Side, deserved a national audience. When Iglauer’s boss, Bob Koester—owner of the Jazz Record Mart and jazz and b...