The Nottebohm Room is everything you'd imagine a traditional reading room should be, all dark wood paneling, inviting desks, and two stories of books that will bring a respectful hush over any book lover. The library's collection dates back to 1481, and includes more than a million books, with 6,000 rare books, folios and other priceless book-related artifacts, including a delicately calligraphed and illuminated history of Rome written by Eutropius . In the early 20th century, the Nottebohm Room was the gathering place for Antwerp's literati -- you can see some more pictures of it here, although the page is in Flemish.
It's my understanding that the Nottebohm Room isn't open to the public regularly, but it's currently hosting an intimate exhibit of modern hand printed books called "Mooi Marginaal", and the contrast between these modern and often whimsical works, along with the nostalgic presence of the entire sweep of publishing history is a fine reason to fit this in when you visit this jewel of a city in Flanders. The exhibit is on until June 14th, Tuesday through Sunday, and admission is free.