Powderhouse is a novel which is set in an asylum for the criminally insane, where the narrator functions as a kind of porter, observing and commenting on the foibles of inmates and keepers alike. The patients are a motley collection, and their treatment is unorthodox to say the least; part of their treatment consists of composing and delivering a series of lectures on subjects dear to their hearts, such as the history of witchhunting and the most humane methods of execution. The doctors themselves have their own troubled history; and the narrator finds rich material amongst both for his study of the follies and evil of which mankind is capable. Yet he is not just a gloomy philosopher, but also a sensualist, and the novel is relieved by passages of lyrical beauty as he enjoys the velvety summer nights, the taste of black bread and white wine, and the gentle caresses of his lover.

This is the first English translation of this novel from 1969 by the controversial Norwegian author Jens Bjørneboe, a man whose irreverent provocations of the sacred cows of his society several times landed him in a court of law. Powderhouse forms the second volume of a trilogy dedicated to exploring "The history of bestiality," following Moment of Freedom (1966), though it stands on its own with a different setting and narrator from the other two.