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. Source: Wikipedia (en)