Caravan’s third album sports a fine cover illustration from Anne Marie Anderson; on the turntable, the album steps up a notch from the group’s previous efforts. Richard Sinclair’s affable (and perennial favorite) “Golf Girl” kicks off; its concise pop, Caravan-style, while “Love To Love You (And Tonight Pigs Will Fly)” offers more of the same. David Hitchcock’s production and the band’s instrumentation are immaculate, while the melodies and lighthearted subject matter are, again, typically Canterbury.

On Aqualung, the lines began to blur between myth and man: Is Jethro Tull Ian Anderson? Is Anderson Aqualung? Is Aqualung Jethro Tull? Like the disheveled character on the album’s cover, or the band’s portrait on the gatefold, Anderson and the rest of Jethro Tull become larger than life with Aqualung-and in fact, became all three.

Step back a few years to the oddly named Uriel, from which Egg was (sorry) hatched; founded in 1968 by bassist Mont Campbell, guitarist Steve Hillage and Dave Stewart, who reportedly only took up the organ because he was intimidated by Hillage’s superior guitar playing. They eventually recruited Clive Brooks on drums through a Melody Maker advert. Uriel played bluesy psychedelia, self-described as part Cream and part The Nice. The band gigged sporadically around London and recorded one album posthumously, released under the more pleasant moniker, Arzachel.

For Atomic Rooster’s next lineup, Vincent Crane teamed up with the talented guitarist John Du Cann, previously in the psychedelic band Andromeda, and Crane’s own foot and left hand (on the lower manual of the organ) instead of a bassist. Ric Parnell briefly played drums, but not before Du Cann instead brought in Paul Hammond. Thus constituted, the trio of Crane, Du Cann and Hammond would burn bright during their short existence. Early in 1971, the band released their second album, Death Walks Behind You.

King Crimson's third album found Robert Fripp and Pete Sinfield back in the studio just months after the release of their previous album, In The Wake Of Poseidon. Andrew McCulloch, post-Manfred Mann, came in on drums, joining the returning Mel Collins and Gordon Haskell (who also provided bass guitar). "Cirkus" opens the album and quickly descends into a typically foreboding Mellotron line; but there is a difference this time around: on Lizard, the Crim sound is exclusively constructed in the studio as this would be the only King Crimson lineup that did not play live.

The title of Van der Graaf Generator's third album refers to "the fusion of hydrogen nuclei to form helium… the prime energy source in the universe." Heavy stuff. Of course, Peter Hammill's lyrics could best be described as intellectual prose; he's usually philosophizing his take on the human condition-ah, the Jesuit education?! Peerless, Hammill's vocal delivery was just as dramatic as the band's music, and one that would polarize: Either you got it or you didn't.

Sometime during King Crimson's first American tour in late 1969, multi-instrumentalist Ian McDonald and drummer Michael Giles decided to part ways with their cohorts (they hated touring). Returning to England, they recorded this eponymous album, enlisting the help of Peter Giles on bass.

Named after Terry Riley’s A Rainbow In Curved Air, Curved Air was another novel group of the progressive era; and the band had no shortage of talent, either. Violinist Darryl Way was a Royal College of Music graduate, while multi-instrumentalist Francis Monkman came from the competing Royal Academy of Music. Seeking to meld their knowledge of classical music and rock, the two joined forces as Sisyphus in 1969, adding drummer Florian Pilkington-Miksa and bassist Robert Martin. They morphed into Curved Air when they added one of the most unlikely of progressive devices-the female voice!

Gentle Giant rose from the remains of the Shulman brothers' pop group, Simon Dupree & the Big Sound. That band had some minor chart success when the single "Kites" b/w "Like the Sun, Like the Fire" broke into the UK Top 10 in late 1967. More surprisingly were the legions of teenage girls that the band attracted, as documented in the British television show Man Alive.

Pink Floyd's fifth album, Atom Heart Mother, appeared a full year after the disappointing studio half of Ummagumma. Originally titled "The Amazing Pudding," the album's side-long title suite was an amalgam of work the Floyd had been kicking around at the time. Of course, 1970 turned out to be the year for adding orchestras to rock music, something to which even the Floyd would succumb. Composer Ron Geesin was called in to score the already-recorded backing track.