Query: Who was Deep Purple's guitarist?
Context: Deep Purple continued to define hard rock, particularly with their album Machine Head (1972), which included the tracks "Highway Star" and "Smoke on the Water". In 1975 guitarist Ritchie Blackmore left, going on to form Rainbow and after the break-up of the band the next year, vocalist David Coverdale formed Whitesnake. 1970 saw The Who release Live at Leeds, often seen as the archetypal hard rock live album, and the following year they released their highly acclaimed album Who's Next, which mixed heavy rock with extensive use of synthesizers.