In the days of yore, authors had their own ways of preventing the theft of their intellectual property:
[B]ook owners were so worried about theft and damage to their property that they often included what is known as a "book curse" on the inside cover or on the last leaf of their manuscripts, warning away anyone who might do the book some harm. And in this, I submit, they were a lot like modern day Hollywood. For a book curse is essentially the same as that little FBI warning that pops up whenever you try to watch a movie: a toothless text charm included by the media's maker meant to frighten the foolish. The charm only works if you believe that words are special, potent magic.
Read the full story at Got Medieval.