Damn good book this one and definitely re-readable which for me is important as I tend to devour good books multiple times. My copy of ADB First Heretic is falling apart now I've read it so often. It does beg the question how Gav Thorpe could get this one so right but screw up the Beast Arises?
Took me a little while to get into these as I was reading them along with Ciaphus Cain and I started getting people confused. A really good series.
Seriously if your only going to read about one non-Space Marine character make it Ciaphus Cain. Normally I can't stand anything written in the first person but these books are just fantastic.
Got all 6 books in this series cheap off Trade Me in two 3 book omnibus's. Inconsistent reads but still worth it if you feel like something a little different. One thing that stood out for me when reading these is just how big a bunch of dickheads some Space Marine chapters can be.