“Future readers, of course, may read their books electronically on Kindles, iPads and the like. In the meantime the real books populate real book stores and libraries. [And] the older a book is, the smellier it is.” So reports PRI’s The World, which recently chronicled the varying reasons that old books smell — and why such a fact might matter.

According to reporter Alex Gallafent, “The smell is made up of VOCs, volatile organic compounds. The VOCs are given off by paper as it slowly degrades, as it dies.” Gallafent goes on to introduce Matija Strilic, at the Center for Sustainable Heritage in London, and who “began analyzing the relationship between smell and paper,” proving that “the smellier the book, the more fragile, the more at risk it tends to be. Now Strilic is developing an extra sensitive book sniffing machine.”

According to Strilic, it’s “An artificial nose with which we could potentially replace the nose of a conservator, or perhaps enhance the scent” and which would more accurately communicate the information curators think they are learning by sniffing old volumes.

The radio reporter also interviews a couple of librarians who claim to be able to learn about the history of old books via smell: one, Thomas Lannon at the New York Public Library, shows off a volume from “Pakistan that’s redolent of onions.” Another, he claims, smells like “pockets, people’s pocket.” Shelley Smith, also at the New York Public, however, claims the same volume smells like “your uncle’s hat.”