Jack the Ripper is the pseudonym given to an unidentified serial killer (or killers) active in the largely impoverished Whitechapel area of London in the second half of 1888. The name is taken from a letter to the Central News Agency by someone claiming to be the murderer, published at the time of the killings. Although many theories have been advanced, Jack the Ripper's identity may never be determined.

The legends surrounding the Ripper murders have become a complex muddle of genuine historical research, freewheeling conspiracy theory and dubious folklore. The lack of a confirmed identity for the killer has allowed subsequent commentators, historians and amateur sleuths â?? dubbed Ripperologists â?? to point their fingers at a wide variety of candidates. Newspapers, whose circulation had been growing during this era, bestowed widespread and enduring notoriety on the killer due to the savagery of the murders and the failure of police to effect a capture, with the Ripper sometimes escaping discovery by mere minutes.

Victims were women earning income as casual prostitutes. Typical Ripper murders were perpetrated in a public or semi-public place; the victim's throat was cut, after which the cadaver was subjected to abdominal and sometimes other mutilations. Many now believe that the victims were first strangled in order to silence them. Due to the nature of the wounds on some presumed Ripper victims, several of whom had internal organs removed, it has been proposed that the killer had a degree of surgical or medical skill, or was perhaps a butcher, although this point, like most of the beliefs about the killer and facts in the case, is in dispute.