As a Miles fan, and particularly his later electric funk, this is a selection of his last Warner albums, with the excellent "Star People" as the standout in a mixed bag of albums. Having bought these CDs (except "The Man with the Horn") in their 1980's issue ('83 - '89), and now upgrading my collection with the later Columbia Legacy re-masters (much better sound - to my ears!), I was concerned as to whether this collection contained the original CD masters or newer re-masters, as I know that the Original Album Classics collections from other artists do contain both old and new CD masters. Now, if you know anything about the Miles archive, and the various releases/re-masters/editions you'll know that it's somewhat complex, and I'm no expert on this. However, I was keen to upgrade my old CD's for better sound, but after much research, couldn't find anything about the source for this collection of CD's. However, I decided that as the collection was a Columbia Legacy issue, I'd take the plunge, and I'm glad that I did. The sound is an upgrade from my original CDs, clearer, brighter, better bass, better separation of instruments, and all at a slightly higher level. I don't know the source of the CDs, perhaps the 20 bit japanese re-masters which were issued in Japan, mainly without any additional bonus material, just like these. The tracks on the CDs, comparing new to old (can't comment on "The Man with the Horn") appear to be the same takes and have very similar timings, except for "Star People", where individual track lengths vary by up to 15 secs, longer ("Come get it"), and 19 secs shorter ("It gets better"), and on "Aura", "Intro" has gained 19 secs, and tracks 5 (Red) & 6 (Green), are much the same length, but the track timings now indicate a different break point (9:57 & 4:24 - old CD, and 6:08 & 8:12 - new CD). As I said, I'm no expert, and my main point is that the CDs do have better (re-mastered) sound than the originals.