Library-book or -materials vandalism, sometimes termed intentional destruction of books or materials[citation needed] or book or material mutilation[1] is the act of damaging or defacing library books or other library holdings. It is a considerable loss of resources for libraries with high rates of vandalism. As with book theft at libraries, vandalism of books has been studied by a number of library professionals.[2][3][4] Librarians consider book vandalism and mutilation a "threat to intellectual property" and have seen it as a "tremendous challenge to the library profession worldwide."[5] Handwriting or marks in and tearing or removal of pages from books can all be forms of vandalism or mutilation.[6] Arson is another form of library book vandalism.[7] The hiding of books within libraries is sometimes considered to be a form of materials vandalism.[6]