The Flight of the Eisenstein (Paperback) - The Horus Heresy Book 4
Not only does this novel continue the story from the epic opening trilogy, it introduces one of the key figures of the series to come: Nathaniel Garro.
His destiny might be murky (and clad in grey), but for now he's a simple Death Guard captain. Find out what drove him from his Legion.
Also, Rogal Dorn finds out about Horus' treachery. Spoiler: he's not happy.
Written by James Swallow