The Diary of Jack the Ripper: The Discovery, the Investigation, the Authentication, the Debate

In March 1992, an out-of-work scrap dealer named Michael Barrett brought a Victorian-looking diary to a London literary agent, claiming it had been given to him by a friend. The diary purported to be the confession of James Maybrick, a Liverpool cotton merchant, admitting to the 1888 Whitechapel murders attributed to Jack the Ripper.

Shirley Harrison's book, published the following year, lays out the diary's discovery, the scramble to authenticate it, and the forensic tests run on its ink and paper — tests that produced conflicting results and became a flashpoint in their own right. It also covers the surrounding cast: Barrett, the Maybrick family, and the historians and document examiners drawn into the dispute.

The diary is regarded by most Ripper historians and forensic document examiners as a modern forgery — ink-dating studies and inconsistencies with Maybrick's known handwriting are frequently cited — and Barrett himself later signed a statement claiming he forged it, though he subsequently retracted that too. Harrison maintained until her death that the diary was genuine. The book is best read as a case study in the mechanics of a disputed document rather than as settled history.