Tokyo is a 2004 novel by British crime writer Mo Hayder.

(For the US market, the title was changed to The Devil of Nanking, which had been Hayder's working-title for the book.)

She travels to Japan in order to find a professor said to have rare footage of the massacre detailing an event that she could not otherwise prove occurred.

The professor decides that he will only show her the tape if she was to procure an unknown ingredient of Chinese medicine from the local yakuza group.

The book deals with the evils of ignorance, Grey being a home-schooled child whose mother heavily censored everything she came into contact with, the politics of modern-day yakuza, and the glitzy underground night-life of Tokyo, as well as the build-up and reality of the Rape of Nanking and the effect it still has today.