This has well been covered over at Deep Purple's site here
It's a 2-Disc Set that comes nicely packaged in a slipcase plus extensive booklet.
Well worth purchasing, Glenn is featured prominently on the MKIII+MKIV material.
The set also includes recently discovered Super-8 material from the Made in Japan Tour.
Excellent quality. Pity you only get to see snippets from each era and not the whole shows - makes you wonder whether there might be more in the archives...
Get it anyway!