I think what Rapaire was saying was the library doesn't keep a database of books checked out by patrons. I can only thnk of very rare occasions when such a databse would be useful to investigators. For instance, when a suspect is known to frequent a particular library, and there is independant evidence to suggest that his or her reading habits are relevant to a specific crime.

Like maybe: "The witness advised the assailant was quoting Dr. Suess."

With computers being used as they are now, it should be as easy to keep such a database as it is for Home Depot or Safeway to have a record of all their customers' sales transactions. Rapaire says libraries aren't doing that yet, so any subpoena for records would have to be satisifed with biographical information, phone numbers, possibly addresses, and currently checked out materials.

As far as using such a (as yet non-existent) database for a random fishing expedition, to find out who's checking out the Anarchist Cookbook, for example, that would seem to be a waste of time in any event. For the very reasons Clint mentions, you're just as likely to snag a curious Republican, or a slightly confused chef, or student with a research project.

If your assignment is to look for subversives, there are just too many fishing holes that would be more productive. The local health food store for instance - "I have a Duces Tecum subpoena for your list of all the people who have purchased alfalfa sprouts in the last six months."