By 1972 Soft Machine had undergone so many personnel and musical changes they really weren't the same band that opened for Jimi Hendrix in 1968. Most of the founding members had left. David Allen had been long gone, moving to France and forming Gong. Robert Wyatt had left and formed Matching Mole (which, if you twist it around a little bit, means Soft Machine in French), Kevin Ayers went solo and was enjoying a healthy success.
All in all, the wildly surreal parts of Soft Machine had gone and the hardcore prog/Experimental Jazz parts stayed. It took some getting used to and the band changed so much over the period of 1970-1973 that a lot of their old fan base left, but were replaced by a new one. Soft Machine by this time had blazed a trail in that area between what was later to be known as Progressive (or Prog-Rock) and Experimental and a lot of musicians were influenced by it. Taking the Free Jazz elements and applying them to rock riffs making a new genre that would be prevalent in the early to mid 1970's. And there was no looking back.
This concert, recorded at the Paris Theatre in 1972 comes about at the end of their stay with CBS Records (Soft Machine 3-7) and right in the middle of their free form/extended solo, instrumental period.
Not for all tastes, but from a historic point of view, crucial in what developed into an enduring genre.