The taboos have worked in my favor. The alimentary recesses hide a lode of unusual stories, mostly unmined. Authors have profiled the brain, the heart, the eyes, the skin, the penis and the female geography, even the hair, but never the gut. The pie hole and the feed chute are mine.

Like a bite of something yummy, you will begin at one end and make your way to the other. Though this is not a practical health book, your more pressing alimentary curiosities will be addressed. And some less pressing. Could thorough chewing lower the national debt? If saliva is full of bacteria, why do animals lick their wounds? Why don't suicide bombers smuggle bombs in their rectums? Why don't stomachs digest themselves? Why is crunchy food so appealing? Can constipation kill you? Did it kill Elvis?

You will occasionally not believe me, but my aim is not to disgust. I have tried, in my way, to exercise restraint. I am aware of the website www.poopreport.com, but I did not visit. When I stumbled on the paper "Fecal Odor of Sick Hedgehogs Mediates Olfactory Attraction of the Tick" in the references of another paper, I resisted the urge to order a copy. I don't want you to say, "This is gross." I want you to say, "I thought this would be gross, but it's really interesting." Okay, and maybe a little gross.

Excerpted from Gulp: Adventures on the Alimentary Canal by Mary Roach. Copyright © 2013 by Mary Roach. With the permission of the publisher, W.W. Norton & Company, Inc.