Even more underrated than Pink Floyd's "The Piper at the Gates of Dawn", "S.F. Sorrow" was recorded by The Pretty Things in Abbey Road Studios during late 1967 and 1968. It was the first rock opera, predating The Who's "Tommy" by a year, which a matter of fact Pete Townshend was aware of. This album is a psychedelic masterpiece. I just started getting into it for the first time, and love it, although it takes a turn for the much darker, atypical to your usual psychedelia. Each song is amazing, and well-constructed. My only misgivings are the lower fidelity of the mono mix due to the tight budget they were given, as well as the primitive stereo mixing on some of the songs. I wish someone would undertake a remix project from the multitracks, because I've had to compile a version using both mono and stereo mixes so that I can enjoy it better. A lot more info on the album here: http://en.wikipedia.org/wiki/S.F._Sorrow