I cleared this through elgecko (not wanting to steal his thunder). Personally, I will always remember this album as the example of seminal Hard Rock...perhaps you do not. For me, it was a September 1972 visit to my HS library. Friends are sitting around, each with headphones, bobbing their heads & smiling. So I jack-in...and man, this is the ****! Anyway, the album was Machine Head...this was my 1st-ever exposure to Deep Purple. I find this strange 'cause I recall having stuff like Zeppelin IV, Yes' Fragile, Tull's Aqualung, AC's School's Out, Sabbath's Paranoid, & Uriah Heep's Demon & Wizards in my collection of approx. 100 LPs. Not sure how I missed this boat on Purple...this was pretty much at the end of the Mk II line-up.