In the early 1970s, Frede Møller-Kristensen stole US$50 million worth of rare books from Denmark’s Royal Library – it was one of the most expensive book thefts in history. He was eventually caught, but only because he died.
Møller-Kristensen was an employee of the library, and beginning some time after 1968 he started taking books home. Not such a huge caper in itself, but (almost) every book printed in Denmark since 1492 had a copy on the shelves of the Royal Library, so he was stealing extremely rare books: first editions of Kant, Milton, and Saint Thomas More, and prints from Martin Luther.
Incredibly, no-one noticed books were missing until 1975. Møller-Kristensen didn’t start selling the books until 1998, earning about US$2 million before he died in 2003. His family inherited the remaining purloined volumes and kept selling them. But if there’s one thing you need to know when selling stolen goods, it’s which ones to never sell.
In 2003, the auction house Christie’s gave the Royal Library a call. Someone was offering to sell a complete copy of a 1517 Spanish novel called Propalladia. There was just one catch: only one complete copy was known to exist. That copy was supposed to be on the shelves of the Royal Library.
The thief’s family all ended up in jail, and about half of the books he stole have so far been recovered.
[An anonymous commenter indirectly suggested this topic; they asked about the creepy cramped bookshelf image that heads this site. The photo is taken from the stacks of this same library, specifically the Black Diamond building. Thanks anonymous commenter!]