During Jack the Ripper's reign of terror, there was an arguably more sadistic and mercurial serial killer operating on the other side of London.

The Thames Torso Killer should, by rights, take precedence over Jack the Ripper as the world's first and most notorious unidentified serial killer. He started to kill in Easter 1887, over a year before the Ripper, and his last murder was in September 1889, almost ten months after the Ripper's last victim, Mary Jane Kelly. The Torso killer murdered and dismembered at least four women, in addition to the unborn child of the only victim who was identified.

The author's profile of the killer reveals a detailed description of his trade, location and movements. She searches against that profile to find a known criminal with a similar modus operandi as the killer. Waterman and lighterman James Crick was sentenced to fifteen years for a single conviction of rape, although charges of rape and attempted murder were brought against him by two women. Crick's method of accosting the women, and transferring them between his skiff and other vessels, explains how the killer secured temporary secure premises for his attacks and dismemberment.

Owing to its overlap with the Jack the Ripper series of murders, this book revisits many of the locations and personalities from that case. It compares and contrasts the Ripper and Torso killer, and the associated police investigations, while paying tribute to river policeman Detective Inspector John Regan.