I have a collection of old books (all 80+ years old), recently, I received a British Chemistry text from 1903 (intro page below) - this being the oldest book of my collection (112 years old at the time of writing this question): 

![enter image description here][1]

One thing I notice is that there is a distinct smell that comes from the pages of older books. (the smell is not unpleasant) - it seems that the older the book, the more distinct the smell.

**What is the chemistry behind the old pages in a book smell?**


  [1]: https://i.sstatic.net/mEFTN.jpg