'The Reasoner of Strange Cases' is a series of books composed of multiple reasoning stories. It tells the bizarre stories of Xu Tiannan, an expert in criminal investigation, who assisted the police in solving a series of strange cases, unsolved cases, and frozen cases during his practice. The hard-line style of police officers who are not afraid of power when facing the powerful also always embodies the ideas throughout the book: fight for the land they love; fight for the disadvantaged groups in the world. The process involves forensic science, criminal investigation and other related terms, but there will be notes below.