Here’s a simply wonderful article on the medieval practice of including a curse at the start of a book, giving a dire warning to thieves and vandals.

“For him that stealeth, or borroweth and returneth not, this book from its owner, let it change into a serpent in his hand & rend him. Let him be struck with palsy & all his members blasted. Let him languish in pain crying aloud for mercy,  & let there be no surcease to his agony till he sing in dissolution. Let bookworms gnaw his entrails in token of the Worm that dieth not, & when at last he goeth to his final punishment, let the flames of Hell consume him for ever.”

Courtesy of Atlas Obscura.

Image credit: A 15th century portrait of a scribe (Jean Le Tavernier/Public domain)