How do I know if former library books for sale really are former library books?

An interesting case where a guy was stealing rare books at libraries across the continent was resolved by some very persistent and observant librarians in Washington. Because the books were very rare, and the libraries where they were from were able to provide thorough cataloging information (such as which pages had writing in the margins, and what that writing was, or which pages had stains or marks) in spite of the fact that the thief removed much of the libraries identifying information before trying to sell them, that didn't stop a small army of volunteer librarians from finding the victim libraries for quite a few of the books. They created a database of the books by finding the said stains and marginalia in the recovered books and then matching those to library catalogs. I understand that over half of the books have now had their original libraries identified, and after the case is resolved those books will be returned. Here's http://www.smithsonianmag.com/history-archaeology/thief-sidebar.html about the theft, and a http://groups.google.com/group/library-security-and-safety/browse_thread/thread/3ccbdbc421c0258b on the case. So, yes, there are such things as databases of stolen library books. But they aren't necessarily on the Internet.

There is such a database for rare books: http://hq.abaa.org/books/antiquarian/databases/stolen_search.html from ABAA

I buy a lot of used books too, and oftentimes these are retired library books. I get loads that don't indicate their retired status. I wondered about it too, until I started attending library book fairs, where the library itself sells their own retired books. Guess what? More often that not, even at the library's own sale, there's no "proof" that these books are legit - though obviously they are. So I wouldn't worry about it.

Short of calling these libraries all over the country, are there any other ways of determining if these books were really retired from collection vs stolen? No. Why would there be? Are you expecting some international database of missing and stolen library books? Just call (or email) the library if you're that concerned. Otherwise go forward in life with the realization that Kant's ethics are a live and well.

Libraries frequently use distributors who allow them to buy new books and then "sell" them back to the distributor. The exchange is actually done for credit toward future purchases. It's a good thing in that it allows libraries to carry multiple copies of new books and then trim back the collection after the fad is over. Don't need 30 copies of Harry Potter or Olivia and the Missing Toy any more, use them as credit toward future purchases, though for a lot less than the original price. But hey, the library lent that copy to probably hundreds of folks before they sold it back and at that point, they didn't need it anymore. The small credit is better than hogging all that shelf space with forty copies of Oliva when the current demand only requires two copies. Or even three when they only need one. The distributor will then sell those copies into the "remainder" market. Lots of remainder dealers then buy them in huge lots, often by the pallet-full. That's where a bunch of those books come from. Those are then sold on the internet or into the retail market. Book Market or Half Price or any number of remainder firms make a good living on these books. The other is the sales libraries themselves frequently offer for titles no one is checking out any more. This raises money for the libraries while freeing up shelf space for new books. Shelf space is finite so good management requires an occasional pruning. Yeah, someone could have stolen and then sold the book, but that's a pretty rare instance. Most (I'd guess over 95%) library copies on the used market are a natural part of the market. You can rest pretty sure your copy has good karma. Trade secret—these kind of sales are often great places to find first editions. If you're into that sort of thing. But because it occurs so frequently, and the books are well used, they are a bit less valuable than your average first edition.

Seconding Jessamyn. If a book is listed in the catalogue as lost or missing, there might be something awry, and you can contact the library to make sure. I did that in the case of a book that is only in a handful of North American libraries and found out that yes, indeed, the book was legitimately withdrawn but the wholesale book dealer who did it neglected to stamp the book as such. You might want to contact the sellers, though, to ask why the books were not indicated as ex-library, just because you didn't expect the stamps/barcodes/whatever. Don't let on that you're suspicious; just express annoyance with the aesthetic drawbacks. If the answer is suspicious, then you might want to contact the library. By the way, old children's books are not necessarily common in libraries--some academic research libraries have a special children's book collection because they are exactly the kind of thing that is not likely to be conserved by a public library or by the public, and they can provide insight into the culture that produced them. If the library marks are from a university library or a major public library like the New York, Boston, San Francisco, etc. libraries (main branch, not neighborhood branches), then you should be very suspicious and inquire with the library.

I recently heard from a librarian at San Diego Public Library that a bunch of their lost/missing books have been turning up via third-party Amazon Marketplace sales. Do as Jessamyn says and check the library's online catalog, if they have one; or call. It'll only take a second for staffers to check whether it's lost/missing or legitimately decommissioned.

Are you expecting some international database of missing and stolen library books? I for one didn't know how universal 'discarded from stock' stamps were until reading this thread.

ms lester and i sell books online via amazon and others. we get our books from a variety of sources, including library sales. sometimes the books are stamped, sometimes not. bookselling is slow work--often things remain in our inventory for years. also, the profit margin is kind of small. too small to justify a trip to the library if we can't find a book. in the few cases where we sold things we couldn't locate, we would either cancel the order, or drop ship it from another vendor. dropshipping is common, we get 1-2 dropship orders a week. it would be very easy for another vendor to sell a 'like new' book, discover that they don't have it, and then make arrangements to dropship our used library book in it's place. but i suppose it could happen.