Schulze’s fourth album was actually recorded before its predecessor, 1974’s Blackdance, but held back. It consists of two side-long tracks, with a 33-minute bonus track added to CD reissues. The first, “Totem,” is a Tangerine Dream-esque journey through deep space, with some electronic pulses to create rhythm but an overall feeling of timelessness and floating. The second, “Mental Door,” is much more active and even hard-charging; some of Schulze’s playing verges on rock organ à la Jon Lord of Deep Purple, and he also sits down behind the drums (his original instrument), slamming out a mechanistic beat that boosts the energy level even higher.

– Phil Freeman