Eisenhorn is a trilogy of science fantasy / crime novels by the British writer Dan Abnett, set in the fictional universe of the Warhammer 40,000 tabletop game. It is the first in a series of trilogies and separate novels by Abnett, which are some of the most popular works of Warhammer 40,000 tie-in fiction.The series follows the inquisitors Gregor Eisenhorn and Gideon Ravenor and their retinue as they hunt heretics and demons, while attempting not to succumb to Chaos – the archenemy of mankind in the setting – in the process. Eisenhorn has been adapted as a video game, and is set to be adapted as a television series. Source: Wikipedia (en)