The Scent of Old Books

Do you have old books at home? If you do, you should agree that the common smell of old books is a mix of vanilla and grass.
There is a reason for that; smell is chemistry and the chemical compounds used in books, i.e. the glue, the paper, the ink, with time break down. Specifically lignin which is present in all wood-based paper is closely related to vanillin.
Old books have always looked great in a home, especially if they come with a hint of vanilla scent...