It's 1793, and Hanno Stiffeniis is a magistrate in Prussia. He has been called to investigate a spate of murders which has reduced the city to a state of terror, under the watchful gaze of his mentor, Kant. Four people have died, and there is no sign of an end to the killing spree.

Tension inside the city is heightened by the imminent threat of invasion; Napoleon is menacing the borders of Prussia, so whilst hunting for the murderer, the city of Konisberg is forced to deal with scheming whores, necromancers who claim to speak with the victims, and the scum of the Prussian army. When the killer tries to murder him, the magistrate finds himself confronted by the demons of his own past. Therein lies the sinister source of those murders, and the true reason he has been enticed back to Konigsberg . . .

Hugely atmospheric, entertaining and intelligent, Critique of Criminal Reason is the first in a series of compelling crime novels set in Prussia featuring Hanno Steffeniis.