Libraries have a longstanding tradition of run-ins with the law. From irate patrons to the Library of Congress hosting the U.S. Copyright office, the law has often been on the library's side. There are points of contention, however. While the library strives to work with law enforcement at every instance, the ideas of patron privacy, patron freedom, and various procedures and policies are there to not only protect patrons but protect the freedom of information.
Patron privacy is kind of a big deal for libraries. It is also a problem libraries painted themselves into. See, a lending library has to lend books and services whether they charge for the privilege or not. It's in the name, lending library AKA most public libraries. Now, back in the day when a public library wanted to give out books, it took your information (and probably due to bullshit of the times, you were a upper/middle class white man) and gave you the materials. That patron info was stored on a bunch of cards and that was that. If someone wanted to know what you read or used, they would have to go through all the cards in all the books and form a list. With the advent of computers and more accessible database structures, all that information became much easier to locate. Enter skilled computer no-gooders who would like nothing more than to hack a library system and instantly have thousands of names, addresses, and phone numbers to send advertisements about penis enlargement pills to. So, there are policies and procedures in place to not only keep your info safe, but what information about you the library collects at all.
So we looked at why the library keeps patron information safe, what about information the patron wants from the library? Ever seen the movie Seven? When looking for the heinous John Doe, Morgan Freeman goes to an old government friend to get info on a bunch of "targeted" books that have been checked out from libraries by people. Well, that's a bunch of crap. Sort of. What about the crazy murderous terrorist serial killers that buy their own copies? Is there another government list for buying odd materials versus being a cheapskate and checking them out? Now, this is a little over the top, especially in the time that movie was written. What can happen now, thanks to dem dare 'puter base datas, is that the government can get a warrant for materials a certain person has checked out or the internet history on a public access computer that has been targeted for excess anti-'mericanism. Most libraries will cooperate fully with releasing this information, either because they feel they should or because they have made their services and patron information nearly useless. Some libraries only keep check-out records on items with fines, losing all items that are returned in a timely manner, or they delete internet histories on a near daily basis. So, if you do not want your library use recorded, return your books in a timely manner and, well, just do not use public access computers. There are ways of making them thar 'puters talk after all.