Mutilation of library materials is a serious problem facing all libraries. Library materials are subject to a range of intentional mutilation.
Some people like to write notes, highlight, or annotate a text in books they've borrowed.
Others mutilate books to convey a personal message of political, religious, or social belief. Books and journal articles are cut out because people can't be bothered to use the photocopier. Some remove pages because they want to be the only one in their class able to read that chapter or article. The UCSD Libraries replace over a thousand pages each month, most of them deliberately damaged. That's a lot of staff time to locate copies in other institutions to make photocopy replacements.