"The Box Man" is a surreal narrative about a man who chooses to live as a homeless individual, inside a box, in Tokyo. The protagonist, a former doctor, narrates his experiences and observations from within the box, and the narrative often blurs the line between reality and hallucination. The book is a philosophical exploration of identity, anonymity, and the nature of existence, challenging the reader's perception of what it means to be an individual in society.

This novel tells the story of a schoolteacher and amateur entomologist who travels to a remote seaside village to collect insects. He is tricked into staying the night in a house at the bottom of a sand pit with a mysterious woman, who spends her days shoveling back the ever-encroaching sand. As the days pass, the man realizes he has been trapped and is forced to help the woman with her endless task, leading to a strange and consuming relationship filled with existential dread and fascination.