I have heard the most important Tangerine Dream albums released in the '70s and this is the most rock-oriented of them all, therefore it was the best starting point for getting into.
There are acoustic passages (Big Sleep, 3 AM), but the synths are the dominant instrument and they do a great job. The band's roots lie in the electronic camp and it still feels, but the fusion here was done greatly. The longer songs (the frame) exploit rather clear prog rock styled structures and build-ups with Invisible Limits featuring an electric guitar solo, as well.
01 Stratosfear 10:04 02 The Big Sleep In Search Of Hades 4:45 03 Am At The Border Of The Marsh 8:10 04 Invisible Limits 11:40 05 Bonus Tracks 06 Coventry Cathedral (the Film Soundtrack) 34:02 07 Stratosfear (single Edit) 4:17 08 The Big Sleep In Search Of Hades (edit) 3:24