The trio consisted of bass player and vocalist John Gustafson, keyboardist J. Peter Robinson and Mick Underwood on drums. Underwood had previously played with Ritchie Blackmore in the Outlaws, while Gustafson had been a member of The Merseybeats. Underwood later became drummer with Episode Six, and was joined by Gustafson after Roger Glover left to join Deep Purple. The band took its name from Professor Bernard Quatermass, a fictional scientist who had been the hero of three science fiction serials produced by BBC Television in the 1950s, and were signed to Harvest Records.
The group formed as a power trio with Hammond organ as the main instrument. Their first and only album sold itself through "...compactness, wealth of ideas, forceful lead vocals and complicated arrangements, enriched by pianist Robinson's tasteful use of classical strings which are on display along with spacious keyboard passages at their height in the mold of The Nice." One track, "Laughin' Tackle", includes 16 violins, 6 violas, 6 cellos, and 3 double bass, arranged by Robinson, and a drum solo by Underwood. Underwood remained in close contact with Blackmore, and visited Deep Purple in the studio while they were recording In Rock.
The group split in early 1971. Gustafson formed a new band, Bullet with ex-members of Atomic Rooster.
The band's song "Black Sheep of the Family" was the first track to be recorded by Rainbow, having been rejected for the Deep Purple album Stormbringer.