If Soft Machine was a rock group that veered towards jazz rock, Nucleus can be seen as a jazz group that veered towards jazz rock, as most musicians were clearly jazz musicians with the notable exception of Chris Spedding (yes, Mr. motocycle-punk/Chameleon-man of rock). If a comparison of those two groups can be made, it is also obvious that Nucleus became a nursing ground for those musicians before joining Soft Machine (around ten musicians did the transfer). They were signed on the famous progressive Vertigo label and the first two superb artwork album sleeves were designed by Roger Dean.
Nucleus was trumpet player (and confirmed jazzmen and biographist) Ian Carr's project and the its discography is rather confusing with the different designations as some were called "Ian Carr's Nucleus", "Nucleus With Ian Carr"…