 The single "Hocus Pocus" was Focus' biggest hit and gained the band international popularity.The song, similar in some regards to the riff-driven hard rock of Black Sabbath and Deep Purple, anticipated many aspects of 1980s heavy metal music, and especially the guitar work of Yngwie Malmsteen with Akkerman's use of the harmonic minor and Hungarian minor scales, uncommon in rock music in the early 1970s.Radical departures in musical styles follow in the remaining tracks of the album.