Jack the Ripper: The Final Solution is a book written by Stephen Knight first published in 1976. It proposed a solution to five murders in Victorian London that were blamed on an unidentified serial killer known as "Jack the Ripper". Knight presented an elaborate conspiracy theory involving the British royal family, freemasonry and the painter Walter Sickert. He concluded that the victims were murdered to cover up a secret marriage between the second-in-line to the throne, Prince Albert Victor, Duke of Clarence and Avondale, and Annie Elizabeth Crook, a working class girl. There are many facts that contradict Knight's theory, and his main source, Joseph Gorman (also known as Joseph Sickert), later retracted the story and admitted to the press that it was a hoax. Most scholars dismiss the theory and the book's conclusion is now widely discredited. Nevertheless, the book was popular and commercially successful, going through 20 editions. It was the basis for the graphic novel and film From Hell, as well as other dramatisations, and has influenced crime fiction writers, such as Patricia Cornwell and Anne Perry. Origins Between August and November 1888, at least five brutal murders were committed in the Whitechapel district of London. Although Whitechapel was an impoverished area and violence there was common, these murders can be linked to the same killer through a distinctive modus operandi. All the murders took place within the distance of a few streets, late at night or in the early morning, and the victims were all women whose throats were cut. In four of the cases, their bodies were mutilated, or even eviscerated. The removal of internal organs from three of the victims led to contemporary proposals that "considerable anatomical knowledge was displayed by the murderer, which would seem to indicate that his occupation was that of a butcher or a surgeon." Media organisations and the police received many letters and postcards purportedly written by the killer, who was dubbed "Jack the Ripper" after one of the signatories. Most of the anonymous confessional letters were dismissed by the police as hoaxes but one, known as the "From Hell" letter after a phrase used by the writer, was treated more seriously; it was sent with a small box containing half of a preserved human kidney. It is not clear, however, whether the kidney truly came from one of the victims or was a medical specimen sent as part