Do you own any books that are withdrawn library books? I do. There’s something inherently grungy-seeming about them, even if they are in pristine condition. You know that more people than usual have touched your book if it is withdrawn, even if it was never checked out. There are also a lot of library detritus left over on the books. Obviously, there is the Withdrawn stamp, usually on the edges and title page, but there are also various other markings, from glued-down Brodart plastic on the dust jackets to library bookplates and stamps to check-out sheets or computer punch cards to those esoteric markings made in pencil by librarians for cataloging purposes in the prelims.
Some people hate having to buy a copy of a book that was once housed in a library, especially a circulating library. I admit to a bit of a bias myself, especially if the edges of a book are well-stained by the thumbs of many a reader. However, sometimes former library books really can be the best copies available because a librarian sometime in the past has cared enough about making sure the book is useful to preserve it. I love old paperbacks bound into sturdy buckram hardcover. That type of cloth will not rip easily and is very hard to stain. Or consider antiquarian pamphlets or ephemera that a librarian somewhere has carefully preserved in a cardboard folder or a plastic slip. Sometimes they even make carefully fitted boxes to house the precious book within!
Library books, especially those from uncirculating research libraries or from museums, can also be exceptionally rare. A specialty library can house one of only a few copies of a particular very specific report ever made. We recently purchased a large amount of books from the Museum of Man in San Diego, whose collection of anthropological texts was truly amazing. (I imagine that a few of the librarians were weeping as they were deaccessioning their collection.) I’ve already cataloged things from this collection that are so scarce that I can barely find records of their existence. For example, they had a book of oral histories from Papua New Guinea that was exceptionally rare. I could only find evidence of two copies of the book ever even existing, and the one they had was made especially for the Museum of Man. Things like that are really hard to appraise, but the more scarce something is, the higher the value. This is one of the priciest collection I’ve ever worked on! And some people don’t value old library books. Ha!