Released in 1972, Deep Purple’s Machine Head launched “Smoke on the Water”—and, in doing so, helped create the blueprint for early heavy metal. The song echoes the British blues of Cream and Jimi Hendrix that Deep Purple grew out of, but also reflects hard rock’s turn toward slower tempos and more brutish deliveries. The lyrcs—inspired by the band’s witness to a casino fire in Montreux, Switzerland—are as repertorial as classic folk, and the harmonies are straight-up psychedelia. And where Led Zeppelin injected blues with elements of fantasy, and Black Sabbath made it sound doomy and occult, “Smoke on the Water” plays it with a sense of historical continuity—the next step in an intergenerational relay race. The members of Deep Purple didn’t want to reinvent the wheel; they just wanted to soup up the engine. It’d be easier to call “Smoke” singular if the rest of Machine Head didn’t follow in step. By the early 1970s, the band had managed to massage their more long-winded pretenses—see the truth-in-advertising of 1969’s Concerto for Group and Orchestra—into a sound that was classic and meaty, but just elevated enough to feel sharp. Deep Purple could make rippers that quoted Bach (“Highway Star”), and could get proggy without sacrificing a good riff or two (“Space Truckin’”). This was a band that never let their own artistic curiosities get in their way of being performers—an old-fashioned attitude that took a back seat as the excesses of the 1970s ballooned. Machine Head was recorded at Montreux’s Grand Hotel, where the group members played in a corridor off the lobby with a recording van parked outside the main entrance. The walk from their performance area to the van was so long—on account of having to detour around the equipment and sound-insulation material—that the bandmates eventually gave up listening to playback of the recordings, and just judged their takes by the raw performance. And if that isn’t a lean and mean recording method, then what is?