We spoke with award-winning science writer Harold McGee, author of the new book Nose Dive: A Field Guide to the World's Smells, a wondrous and entertaining guide to the smells of food, yes, but also of our surroundings—indoor as well as outdoor, from rotten eggs and wet dogs to coffee and perfume—and offers readers a whiff of the very building blocks of the universe itself.

Harold McGee on the science of smells