One of the most unique and little-noted features of the dead-tree reading platform is its smell. A crisp new edition of Pride and Prejudice is scented a whole lot differently than the musty, middle-aged printing still being read in many a high school English class today.

But what causes these smells? A UK chemist and teacher who runs the blog Compound Interest, an exploration of everyday chemical compounds, went to investigate and came up with an infographic to explain the matter.

Read More: What Makes Old Books Smell Like Old Books? | Co.Exist | ideas + impact