Science writer, Mary Roach, started out as a magazine journalist, but eventually parlayed her column for Salon.com into her first book, Stiff: The Curious Lives of Human Cadavers. Next, she investigated the afterlife in Spook: Science Tackles the Afterlife, then came Bonk: The Curious Coupling of Science and Sex.
In Gulp: Adventures on the Alimentary Canal, Roach dives into the human body, beginning at the mouth, then moves, um, downward as she discusses digestion and elimination.