This box is obviously a diehards-only item; if you even have to ask yourself whether you should own it, you’re already in so deep that the only answer is … Yes. (The day it was announced, I joked on Twitter that since they’d already called previous live releases Yessongs and Yesshows, this one should just be called Yessss.) As its title suggests, it’s a 14-CD set containing seven full shows from the 1972 tour supporting Close To The Edge (which is performed in its entirety, though not in sequence). This was the same tour on which the bulk of Yessongs was recorded, and there are a few tracks here that also appear there. But the overwhelming majority of the material is previously unreleased.

The set list is as follows: “Siberian Khatru,” “I’ve Seen All Good People,” “Heart Of The Sunrise,” “Clap/Mood For A Day,” “And You And I,” “Close To The Edge,” “Excerpts From The Six Wives Of Henry VIII,” “Roundabout,” “Yours Is No Disgrace.” On the first concert in the box, “Clap/Mood For A Day” comes before “Heart Of The Sunrise,” but other than that, there are no changes from night to night.

The differences between these shows are relatively small. The set list is exactly the same from night to night, with the exception of the concert on discs 1 and 2, where two songs are flipped. And while there’s improvisation (particularly on guitarist Steve Howe’s part), Yes were not King Crimson, journeying into uncharted instrumental waters night after night. This is highly disciplined, complex prog-rock; if one person misses a measure, the whole structure comes clattering down. But at the same time, they weren’t chamber musicians reading from a score; they were an absolutely smoking hot rock band in 1972. Howe and Alan White repeatedly demonstrate an intensity that’s almost breathtaking, particularly on the versions of “Yours Is No Disgrace” that close the shows. And it’s worth remembering that, for all its power, Yessongs was tweaked after the fact (not to the degree of Kiss’ Alive or Judas Priest’s Unleashed In The East: Live In Japan, granted, but still), with extra layers of vocals and some instrumental polishing added to the recordings. Progeny, on the other hand, is a restoration of the original multitrack recordings, as pure and historically accurate as it gets. So basically, if you’re the audience for this box, you will be blown away by it.