"The Professor and the Madman: A Tale of Murder, Insanity and the Making of the Oxford English Dictionary" by Simon Winchester.
Also published as "The Surgeon of Crowthorne: A Tale of Murder, Madness and the Love of Words" outside of the US, and so it took me a while to track it down after it was recommended to me, and then took me a while to realise it was actually the same book that someone else had recommended to me by the other name!
My score: 6.5/10 Really fascinating story and loved hearing how the dictionary came to be made, seems like an impressively large and wonderful example of "citizen science" or linguistic scholarship. There was a fair bit of repetition in the telling, and took a while to really get to the making of the dictionary, as a lot of the book dwelled on the mental state of the Surgeon (William Minor), his sexual fantasies and paranoid delusions and speculations on the causes of these. I was often unsure if this was 'non fiction' or 'historical fiction' as so much of the book seemed to be speculation based on historical notes and focusing on the peculiarities of the Surgeon, rather than the making of the dictionary and his contributions to it. The most interesting part of the story for me was the role William Minor played contributing to finding definitions and quotes for the development of the Oxford English Dictionary while being a long-term inmate of a mental asylum, and the relationship between James Murray who edited/compiled/orchestrated the OED.
I have also heard good reviews about a recent historical fiction book called "A Dictionary of Lost Words" by Pip Williams, which looks at the making of the Oxford English Dictionary from a more feminist perspective, and I am very keen to read that.
Genre: Non fiction? Historical fiction?