|Old book bindings at the Merton College library, 2005 - photo by Tom Murphy VII, Wikimedia Commons|
The International League of Antiquarian Booksellers (ILAB) has an interesting little article about that "old book smell." Apparently, it's more than just mustiness or mildew - the components of old books produce odors that resemble grass and vanilla! It's even possible to determine the age of some books based on their VOC's (volatile organic compounds). It's a matter of personal preference if you like that smell or not - guess it depends on the book too.