So, whilst I was on holiday I learned about a book known as The Codex Gigas, also known as "The Devil's Bible". This isn't something you could curl up with on a sun lounger.
As is the case with mysterious objects like this, the reality is as bizarre as the legend. According to the myth, a monk called Herman The Recluse broke his monastic vows and was sentenced to be walled up alive. In order to avoid this harsh penalty he promised to create in one night a book to glorify the monastery forever, including all human knowledge. Near midnight, he became sure that he could not complete this task alone so he made a special prayer, not addressed to God but to the fallen angel Lucifer, asking him to help him finish the book in exchange for his soul. The Devil completed the manuscript and the monk added the Devil's picture out of gratitude for his aid. It's a lovely bedtime story, but the strange thing is the writing itself is remarkably even and consistent, meaning it appears to have actually been written by one man or woman in a stunningly short amount of time. For context, it is estimated that reproducing only the calligraphy, without any of the illustrations or embellishments, would have taken five years of non-stop writing.
This behemoth of a book has actually injured somebody too - in 1697, a fire broke out at the royal castle in Stockholm, and the Royal Library suffered terribly. The codex was rescued from the flames by being thrown out of a window. This damaged the binding and knocked loose some pages which are still missing today. According to the vicar Johann Erichsons, the codex landed on and injured a bystander.