“There I was, reading On Opera by the late philosopher Bernard Williams, and I was suddenly transported back to my childhood. How so? Because of the way it smelled. … How to describe why one book smells nicer than another? I could burble on about the Williams book’s hints of musk, fresh grass, and topnotes of vanilla, but you can see that I’d never make it as a wine writer. But maybe there is a secret community of book-sniffers out there who know what I mean.”