From Warseer:
Quote Originally Posted by SunTzu
Horus Heresy book, first in a series, based around Isstvan III. To be announced at Games Day (...though not sure whether that's UK or USA).

...I mean, I guess.
SunTzu has a very good record with FW releases, he had details on on the new WarForge book and a few other things before they were revealed at Games Day.

I just hope it is wrong. I get all the love ofr the HH and I'm all for FW making some pre-Heresy kits and whatnot but I feel the Heresy has been de-mystified enough without having FW making a series of campaigns out of it. Not to mention we already ahve IA which is basically MArines/Guard vs Marines/Guard & sometimes Xenos. Now we get another whole book of Marine vs Marine. Thrilling.