There were a total of five books in the " Mental Crime " series in China: " Mental Crime,"" City Light,"" Enlightenment Field,"" Heart of Darkness," and " Eye of Light." The series used criminal psychology as the theme to show the darkness and distortion of the human heart through true crime stories, as well as the struggle and redemption between light and darkness. The series was loved by readers and was hailed as one of the representative works of contemporary Chinese detective novels.