First chapter is now on Tor's website, while chapter 2, 3, and 4 are now on Halo Waypoint. Even the opening chaptershave some intriguing reveals. Seems Primordium ties in with The Return. Chakas, it would seem, is the AI the humans found, and the Shipmaster is looking for. Its revealed in the opening few pages that Chakas has had contact with the Covenant, too. Chakas may be Abject Testament. The UNSC are very interested in the Didact for some reason.
Those human-like temples we saw in Halo 2 now take on a whole new significance.
I think in Halo 4 as well as Cortana going rampant, we may see the Chief's "geas" being re-awakened and him reliving ancient memories. Maybe John-117 has the imprint of an ancient human warrior who fought against the Forerunners?
I can't wait to read this book. The spoilers I've read do not shed nearly enough light of my tastes (at least I hope it's not as disjointed as it appears to be, or this is even less resolved than Glasslands). Not a lot to add to the timeline, but a lot of interesting (if not predictable) happenings.
Got a Halo story question? http://www.gamefaqs.com/boards/632877-halo-4/59577580