The initial CD issue of the double album length Incantations was bowdlerised by 3 minutes, supposedly to fit onto a single disc, rather daft as the full version is only 73 minutes. Fortunately this was rectified in later versions, and after I recently picked up one of those at a secondhand shop, having had the cut version for a decade, it seems astonishing to me what difference those three minutes makes. Because I never really rated this as a decent Mike Oldfield album. I felt it was too long and over-ambitious, and in fact quite annoying in parts. In fact, in review, this is about as close as Oldfield's work gets to the "serious composer" aesthetic of Steve Reich and Philip Glass. After this album, only The Killing Fields soundtrack (1984) and Amarok (1990) have approached this level of complexity as whole albums. (Oh yes, Rory, and "Afghan".)
But on with the music; there are not the explosions of hot bliss that made Ommadawn (1975) such a formidable work, rather, the pleasures here are more zenlike - listen too hard to the more repetitive aspects and you are bound to get bored. Still, most of the more delicate moments occur on the first vinyl, particularly the conclusion to Part 2 with Maddy Prior (then of Steeleye Span) as chanson. In setting up the thematic chord progressions, hammering it into your head using the devices of chanting choirs, string sections, vibraphone and synths, the more subtle aspects start to reveal themselves in a hypnotic fashion.
The beginning to Part 3, originally excised, is a revelation; at first listen it's just a inconsequental piece of pomp rock, but its place is in setting up the next part - a section of the vibes and the Jabula African drummers, appearing nice and placid from afar, but the undercurrent of the rhythm guitar adds a sense of Ommadawn-esque tension to proceedings, before shortly Oldfield's best guitar lead of his career to date begins to careen overhead. This piece thunders along nicely, interlocking into a couple of more fusionish, driving sections to finish off Part 3. The first half of Part 4 is dominated by vibes playing the perpetually ascending theme ad nauseam, so after the languid opening, skip to 8:00 when things improve a lot, firstly with a curiously robotic yet Eurogroovy arrangement which presents hints of his better eighties work to come, and then the finale with the return of Prior singing over, plus more vibes, of course, one of Oldfield's best melodies. A real payoff after over an hour of alternatively tedious and brilliant setting up.
All in all, not the Mike Oldfield album for neophytes (the aforementioned Ommadawn may be all you want, 1994's Songs Of Distant Earth is also a good place to start), certainly it has taken me a whole decade to really appreciate Incantations.

Hey, what happened to the comments box on Incantations? I know it's taken me a while to get around to commenting, but still. (Be a bit quicker next time! :) - Ed.)Very well, I'll put my comments here.
Good points about the bowdlerisation. Having started out with the double LP, I hated what they'd done on the original CD, especially since it was actually unnecessary even by the CD standards of the time. But they did some weird shit with CD reissues in the 80s.
Incantations is one of those albums, I think, where running it all through in one hit - as CDs make possible and almost inevitable - actually ruins the effect. It's definitely a four-sider, and benefits from having to pause for a few minutes between each side while you get up and flip the disk. Try playing it one track at a time, with 5-10 minutes between each, and you'll see what I mean.
This is true of all of Mike's early albums, I think: each side is like a movement in a symphony, quite different from the other. This is especially noticeable in Ommadawn.
Compare this to Amarok, which is breathtaking for being the exact opposite: a one-hour stream of music. There's actually a spot where you can break it in half (for the benefit of the cassette and LP versions), but in this case doing so detracts from the whole.