I saw this on Tumblr, and I had to put it here. Apparently a town opened a new library, and as part of the festivities, asked a bunch of writers at the time to write letters about libraries to the town's children. This is the one that Isaac Asimov wrote. I've rarely seen a better summation of what libraries are for.
UPDATE: Wow, this post is apparently generating a highly unusual amount of traffic to my little old outpost on the Interweb! Hello to all new visitors, I hope some of you stick around...but I'm not sure of the source of the traffic, which seems to be coming from mail servers, which leads me to believe it's a post on a Listserv or some other kind of mailing list. If someone wouldn't mind dropping a bit of background as to where you're all coming from in the comments, I'd appreciate it!