As a young medical student at Edinburgh, Sir Arthur Conan Doyle took classes with the remarkable Dr. Joseph Bell in forensic medicine. Dr. Bell exhibited many of the characteristics that Doyle would later synthesize into the personage of Sherlock Holmes: complete faith in human reason, meticulous powers of observation, and encyclopedic knowledge of the activities and methods of the criminal classes.
In his novel, David Pirie pairs Bell and Doyle as Doyle would later pair Holmes and Watson, as pioneers in criminal investigation, looking into the seamy underside of the proper Victorian world. Doyle is puzzled by the ocular symptoms of a woman in his medical practice. Bell senses that there is something criminal afoot, and...the chase is joined.