Perhaps the most well known of all the world's serial killers, Jack the Ripper continues to befuddle would-be investigators and inhabit the nightmares of children and adults everywhere. However, although people are well aware of this monster, even now a century and a half after the killings began, conflicting opinions still abound as to Jack's true identity.

In this book, Frank Emerson has uncovered a previously lost narrative by Dr. John H. Watson that illustrates how he and Sherlock Holmes, working in tandem with Detective Chief Inspector Frederick Abberline of Scotland Yard, conducted an intense fifteen-year investigation and pursuit that culminated with the unmasking, arrest, trial and ultimate execution of the real Jack the Ripper.