W40k Rules come in a hard cardboard box and includes 3 separate books.
The first is called Galaxy War and is a starter guide with 114pages with lots of photos of painted miniatures. The second is called Dark Millennium and is 128 pages with extensive background section and new portraits and illustrations. The third is the rules, and is 208 pages including among it the new psychic powers. - translated from Spanish
So looks like Visions of Dark Millennium is the fluff book. Hilariously, the psychic phase expansion and rules from 2nd edition were called Dark Millennium.
This release is seriously bringing back everything about 2nd Edition that got me into the hobby and I am like a fat diabetic in a candy store.
Wait. I AM A FAT DIABETIC. THIS IS AWESOME.