Avery Gilbert is the David Sedaris of the nostril, the Mark Twain of the nasal passages. In this irreverent tome, he manages to interweave olfaction and the science of smell with virtually all aspects of human endeavor, from the scatological to the heavenly. This fun, relaxed approach can be vaticinated from the opening page, which quotes the 1967 Mad Magazine satire “Fantastench Voyage.” Like the Ygdrasil, the mythical Norse ash tree that unifies heaven and earth, Gilbert seamlessly intertwines the scientific with pop culture, enlightening the reader all the while about common, oft-repeated olfactory misperceptions. For instance, how many odors can humans detect? 10 000? 30 000? 400 000? As Gilbert traces the evolution of this answer, he exposes the number as a myth perpetrated from generation to generation of smell researchers, like a perverted game of telephone. (The answer: no one knows.) He similarly debunks concepts of sophisticated noses that can detect components of aromas to the nth degree, citing experimental data demonstrating that in a mixture of 3 or more odors, less than 15% of individuals tested can identify even a single component. He also cites the Laing limit, which maintains that even well-trained perfumers and flavorists can identify no more than 4 odors from a mixture.