Inquisitor Gregor Eisenhorn has spent his life stalking the darkest and most dangerous limits of the Imperium in pursuit of heresy and Chaos. But how long can a man walk that path without succumbing to the lure of the Warp? Is Eisenhorn still a champion of the Throne, or has he been seduced by the very evil that he hunts? Warhammer 40,000's most beloved anti-hero finally returns in a stunning new novel that pits him against his oldest and most constant foe, and forces him to confront the true darkness of his own self. For the first time ever, the Black Library presents the definitive casebook of Gregor Eisenhorn, collecting all of Dan Abnett's celebrated Inquisitor short stories into a single epic volume. The stories, some of which have never been in print before, have been compiled and introduced by the author to serve as an indispensable companion to the acclaimed Eisenhorn trilogy, and to act as an essential prologue to The Magos, a brand new, full-length Eisenhorn novel.