This was a great read, but it must be said that you would have to be a loremaster amongst WH40K loremasters in order to really keep up. An Inquisition-centric novel at its heart, but it pulls into it nearly every element of the Imperium's warmachine into the sprawling narrative and so I think the vast majority of readers will be put off. We have Rogue Trader dynasties, Ecclesiarchy, Navigators, Mechanicus, Army, Navy, Arbites and multi-layered politics of the Inquisition rearing its ugly head. Just about the only thing we don't see are Space Marines, which is refreshing to be perfectly honest!

With that caveat in play, I think this is one of the better entries into the WH40K universe. But let me get off this off my chest... I dislike is the naming. Horusian Wars make this sound like an epic story: crusades falling, millions of worlds lost, the galaxy aflame etc. The actual scope is relatively tame in comparison. Horusian Schism is probably more accurate.

If you get past that, the central plot and mystery include plenty of bolter action. I enjoyed the politics. It starts off very rough, with a wide variety of characters introduced page after page without a real understanding of how any of them relate. But once it gets going it's easy to remember who is who, and the cast is varied and interesting enough to dress up the central plot. If you are deep into WH40k lore, I highly recommend Resurrection.