Alright, turns out I lied. The book does contain info on the Lost Sanctum and the Dimensional Vortex.
The bad news is that it's so scant, that that's the reason I missed it in the first place. Both extras get a mere two pages each, neither detailing anything remotely useful about either dungeon set. Especially in the case of the Dimensional Vortex which only outlines where the three gates are, and what the maps for the gates look like. That's it. No strategy on any bosses, nothing.
The rest of the book serves as a fairly good guide to the game, with a list containing all teches, a full bestiary (Save for any creatures new to this version), and various info on every time period. Nothing enlightening in the least, but if you don't already know CT like the back of your hand, I certainly can't see you purchasing a worse guide at the moment (Given it's the only one available right now...).
I'd advise people wait though. When Sigma Harmonix had first came out, a third party guide was released, and then a few months later, SE released one with interviews, etc. They always do that, so you're better off waiting for the SE- super dooper better than all the rest buy our shit-version of the guide.