Old books have a distinctive scent that can transport us to another time. This smell is caused by a combination of chemical compounds released as the book slowly decays. Scientists are now using these volatile organic compounds (VOCs) to learn more about a book’s age, condition, and history. Paper is made of cellulose fibers bound by lignin, and inks and bindings add additional organic compounds. As these materials break down over time, the VOCs are released into the air, creating the characteristic smell. Analyzing the VOCs can reveal information about a book’s origins and even help match orphaned books with their original library.
https://scienceswitch.com/2023/08/19/why-do-old-books-smell-so-good/