This is a cool book I picked up recently: The Card Catalog: Books, Cards and Literary Treasures, written by the Library of Congress. It's a cool blend of history and visuals, and if you're nostalgic at all for the days of the card catalog or even libraries, it's well worth picking up.
The book alternates between two sections: images of the Library of Congress's collection, showing off books and their card counterpart, and history.
The history is the most appealing thing for me. It takes the reader through the history of the card catalog, with a broad view of how the library system itself came into being. From the very first Library of Congress to the present, it talks about something that people don't think about much when it comes to libraries: how an organization ... organizes itself, and how that helps steer the mission and purpose of the institution from thereon out. The actual cards are interesting, but it's the way in which they're used that's most fascinating. Now that computers have largely taken over the task of locating books in a library's collection, understanding that organizational mindset is pretty important. What I found most interesting is that the LoC actually still has their catalog in place, and the cards are still incredibly useful for researchers and librarians.