Written by the American writer, Gene Wolfe, Nightside of the Long Sun is the first book in a series of four books collectively named The Book of the Long Sun.
The action takes place in one of the poor districts in the city of Viron, located on a world called the Whorl. A priest named Silk is charged by a dark god to save his parish threatened by a mobster. From here starts a series of adventures or rather a chain of accidents more or less controlled by which the young priest begins to discover the truth about the nature of the gods whom the world he lives in, also worship them. Within two days Silk becomes friend with a burglar, enters by burglary in a house, struggles with a huge bird, steals weapons of mass destruction, solves a murder mystery, exorcise a brothel and so on.
All these events are narrated with humor and brevity. The book begins a little difficult, like any journey into an unknown land, but then it becomes impossible to be let out of hand. All pleasure is to put together the clues and solve the puzzle. So go and read the Nightside of the Long Sun now.