Starred Review In her latest rollicking foray into taboo, icky, and underappreciated aspects of the human body, best-selling science writer Roach takes readers on a wild ride down the alimentary canal. Not that the author of Stiff (2003), Bonk (2008), and Packing for Mars (2010) ever takes a direct route anywhere. No, voraciously curious and intrepid Roach zips off in whatever direction her ardor for research and irrepressible instinct for the wonderfully weird lead her. She begins this hilarious, mind-expanding inquiry into eating, digestion, and elimination with the symbiosis between smell and taste, guided by an olfactorily gifted "sensory analyst," then profiles Horace Fletcher, proponent of a rigorous chewing routine known as "Fletcherizing" practiced by Henry James and Franz Kafka. We learn more than one can imagine about saliva and our passion for crispy and crunchy foods. Given Roach's fascination with what we find disgusting, scientific obsessions and bizarre experiments, and horrifying things we do to ourselves, the stories get stranger as she proceeds down the body. Roach interviews a prison inmate about "rectal smuggling" (including cell phones), tells tales of flatulence, and reveals the truth about Elvis Presley's fatal megacolon. For all her irreverence, Roach marvels over the fine-tuned workings and "wisdom" of the human body, and readers will delight in her exuberant energy, audacity, and wit.

Throughout her sojourn down the gastrointestinal tract, science writer Roach (Packing for Mars: The Curious Science of Life in the Void, 2011, etc.) enlists her abundant assets of intelligence and humor while dissecting this messy and astounding part of the human body. The author ties her curiosity about this region of the body and what many consider a disgusting or off-limits subject for polite conversation to a fifth-grade classroom encounter with a headless, limbless, molded-plastic torso: "Function was not hinted at in Mrs. Claflin's educational torso man….Yet I owe the guy a debt of thanks. To venture beyond the abdominal wall, even a plastic one, was to pull back the curtain on life itself." The author begins by detailing the subtle, complex role the nose plays in taste; why humans have trouble finding names for flavors and smells; and how the human nose can be thought of as a "fleshly gas chromatograph." Roach chronicles her visit to an oral processing lab and her interview with a prisoner who patiently explained the intimate details of utilizing the alimentary canal for illegal purposes. The author grapples with the history of flatulence and adeptly describes the torment caused by Elvis Presley's megacolon, which ultimately caused his demise. She also fleshes out just what constitutes the "ick factor" in this tale of ingestion, digestion and elimination. Roach's abundant footnotes serve as entertaining detours throughout this edifying excursion. When a topic heads toward sketchy territory, the author politely provides a heads-up for squeamish readers. Whether Roach is writing about lateral tongue protrusion, the taboo surrounding saliva or whether "rectal consumption of beef broth breaks one's Lenten fast," the author entertains with this incredible journey into the netherworld of the human body. A touchy topic illuminated with wit and rigor, packed with all the stinky details.