Early on, Styx's music reflected such then-current prog rockers as Emerson, Lake & Palmer and the Moody Blues, as evidenced by such releases as 1972's self-titled debut, 1973's Styx II, 1974's The Serpent Is Rising, and 1975's Man of Miracles. While the albums (as well as non-stop touring) helped the group build a substantial following locally, Styx failed to break through to the mainstream, until a track originally from their second album, "Lady" started to get substantial airplay in late '74 on the Chicago radio station WLS-FM.
The song was soon issued as a single nationwide, and quickly shot to number six on the singles chart, as Styx II was certified gold. By this time, however, the group had grown disenchanted with their record label, and opted to sign on with A&M for their fifth release overall, 1975's Equinox (their former label would issue countless compilations over the years, culled from tracks off their early releases). On the eve of the tour in support of the album, Curulewski abruptly left the band, and was replaced by Tommy Shaw (sadly, Curulewski would pass away from an aneurysm in 1988). Shaw proved to be the missing piece of the puzzle for Styx, as most of their subsequent releases throughout the late '70s earned at least platinum certification (1976's Crystal Ball, 1977's The Grand Illusion, 1978's Pieces of Eight, and 1979's Cornerstone), and spawned such hit singles and classic rock radio standards as "Come Sail Away," "Renegade," "Blue Collar Man," "Fooling Yourself," and the power ballad "Babe."