The criteria for deselection (also called "weeding") of books and other materials in a well-run library is as follows:

-The circulation statistics no longer support it taking up space on the shelf. For instance, if an item has not circulated more than ten times in the past ten years, and not once in the last three, that can be considered inactive. This criterion can be mitigated by certain factors, such as the status of the book in its usage group. Little Women doesn't circulate as much as it used to, but I would never ever get rid of it because it's a bona fide classic. Interest in such books always picks up again after a bit, and adults will come looking for them too. Other materials of this nature are those associated with holidays or annual school assignments. The only go out during October, say, or February, but boy do we need them then.

-It is in poor repair. One ripped page is usually mended. But modern books have, on the whole, awful bindings. I can show you books that I know are not going to stand up to another year of library usage by tell-tale signs that you might not notice. These books will be happier, and better used, in the personal libraries of people who will read them a couple of times and put them on a shelf or give them to a friend, or who will read them on the beach and then throw them out. We shouldn't have to pay to throw them out after they fall apart in six months when we can make three bucks off of them at the book sale.

-It has been defaced. This should be obvious, and is to people who deliberately deface books knowing they'll be withdrawn. I will usually replace such books immediately, and as often as it takes for the vandal to get the point: it's not going away. In the case of children's books, the reason is more basic: a child who sees a library book that has been written in, colored on, or smeared with jam will conclude that this is normal and fine. So we must model the kind of behavior we expect them to follow by giving them things that, even if old, are still reasonably close to unmarked.

-It is one of multiple copies purchased to satisfy earlier customer demand that has since dwindled. We needed three copies of Stephenie Meyer's Breaking Dawn and the new mystery by Janet Evanovich. Some larger libraries would need five or ten. But after the fans finish these books, and this is also true of political non-fiction best-sellers, they sit there a matched set, taking up space. At that point we withdraw all but one. That's all that's needed.

-They're out of date. Literature doesn't go out of date, but science & technology books do. Books about law do. Biographies do, unless the subject is dead. Out to the booksale! Or sometimes, out to the trash. I would never ever sell a used book on the treatment of AIDS from the 1980s to anyone. It would be irresponsible.

Other libraries have other issues. The library in the town where our family has our vacation home is very small and bound by roads and a railroad on all sides. It lives in a turn-of-the-20th-century train station, so the building's historical value limits the amount of expansion that can be done. For every new item the librarian buys, she has to withdraw one, because they literally have no more space. She says it's painful work, and I believe her. She's ruthless, though, and they have one of the best used book sales I have ever been to.

A word to Tech, on your nickel: If you have concerns about the things being withdrawn at your library, ask to see their collection development policy. After you read it, you can ask the librarians to justify the withdrawal of anything based on their policy. I bet you they can.

As for the stickers, that's processing and prep for circulation, which has nothing to do with selection and withdrawal, or censorship. It's done the same way for everything, often by people who care more about process than content. Many libraries job this process out to the companies from which they make their purchases. It doesn't matter to the person performing this task what the sticker conceals, as long as it's in the place where the manual says to put it.

Sometimes, things that seem nefarious are just dumb. To know the difference, you have to look at the overall pattern.