"Quatermass' only album is a must-have for prog rock enthusiasts, especially lovers of the keyboard-dominated style which flourished in the early '70s. Although there are only three members of the band, their histories are just as colorful as the music they produced. Keyboard player Pete Robinson and bass man Johnny Gustafson met drummer Mick Underwood and founded Episode Six, a band which included Ian Gillan who later fronted Deep Purple. Underwood was also involved with the Outlaws as well as the Herd, only a few years before Peter Frampton arrived. When the band finally formed Quatermass in 1970, they had set their sights on a power rock format which would use Robinson's keyboards to shape their sound. Both "Black Sheep" and "One Blind Mice" were released as singles which fell mostly on deaf ears, but the band's sound was equally as moving as the Nice's repertoire, for example, at around the same time.

Quatermass' sound is far from sounding hollow, isolated, or directionless, but all of the cuts are rather rock-sturdy and instrumentally voluptuous from all points. The string work that swoops in is encompassing, Underwood's drumming exhibits personality, and the keyboard portions are remarkably striking and distinct. Even Gustafson's robust vocals work well within the music's structure, subsiding and ascending when called for, and all of the cuts result in worthy examples of well-built progressive rock, in both ballad and power rock form. Following this album, the band broke up, with Gustafson later doing session work for Kevin Ayers, Steve Hackett, and Ian Hunter, among others, while Robinson found new life within the jazz-prog band Brand X. Beautifully packaged with informative liner notes, Quatermass sounds as resounding today as it did in 1970, and upon hearing it, one can only wonder why it was so overlooked during its release." - All Music