My rating: 4 of 5 stars.
My first encounter with Warhammer 40k literature, and it was a good one. I only marginally knew what the franchise was all about, but the Humble Bundle containing the full Horus Heresy cycle won me over.
Even without any foreknowledge, the book is very enjoyable. You’re thrown right into the, extremely large, world but bit by bit the author expertly explains key facts. He does this so good, the (rapid) speed of the story never breaks and you get sucked right into the brutal world of Horus, Loken and the Luna Wolves.
The only drawback is the fact that the book was clearly never meant to contain a finished story and merely acts to prepare for the next book. In we go then: Lupercal!