After satisfying all of their classical music kinks with keyboard player Jon Lord's overblown Concerto for Group and Orchestra, Deep Purple's soon-to-be classic Mark II lineup made their proper debut on 1970's awesome In Rock. The cacophony of sound (led by Ritchie Blackmore's blistering guitar solo), which introduces the opener "Speed King," makes it immediately obvious that the band is no longer fooling around. The slightly less intense "Bloodsucker" allows for some breathing room before the band embarks on the album's epic, ten-minute tour de force "Child in Time." In what is arguably his greatest performance, singer Ian Gillan leads the band on a series of crescendos, from the song's gentle beginning through to its ear-shattering climax, and back again to an even more intense encore. With searing power chords, "Flight of the Rat" is another example of the band's new hard-rock stance; though at nearly eight minutes, it too finds room for some extended soloing from Blackmore and Lord. "Into the Fire" and "Living Wreck" are more concise but equally appealing, and despite the closer "Hard Lovin' Man," which waffles on a bit before descending into feedback, this is still an essential album.