A Field Guide to Human Flatulence

Everybody does it about sixteen times a day. Almost nobody understands it.

A Field Guide to Human Flatulence is a clear, surprisingly rigorous, and genuinely funny tour of one of the body's most universal and least discussed functions. Following a single mouthful of food on its complete journey - from the lips, through the stomach, and down twenty-odd feet of looping intestine to its inevitable exit - this book explains exactly where intestinal gas comes from, why some farts are silent and some announce themselves, and why a vanishing one percent of the cloud is responsible for one hundred percent of the trouble.

Written for curious readers of every age, it answers the questions you were too polite to ask:

• Why is most of a fart just swallowed air?
• What are the trillions of bacteria in your gut actually doing down there?
• What separates a burp from a fart? (A few feet of plumbing and a difference of opinion at the gates.)
• Why does volume have nothing to do with smell?
• What does your diet really change - and what doesn't?

Along the way you'll find chapters on the science of the sound, the chemistry of the smell, the truth about what counts as "normal," and practical, no-nonsense looks at how diet and lifestyle shift the dial. A tour through the cultural history of human beings being weird about this very normal thing sits alongside a visit to the rest of the animal kingdom - where cows, termites, and even herring all have something to contribute.

For readers who want to go deeper, a clinical appendix covers the medical conditions behind problem flatulence, complete with a clear-eyed guide to when something is just dinner and when it's time to call a doctor.

Equal parts physiology, field guide, and gentle comedy, A Field Guide to Human Flatulence proves that the body's exhaust system is far stranger, more elegant, and more interesting than anyone gave it credit for.

A working gut is a gassy gut. You may as well understand yours.