If you’re not a fan of what happens to your food from one end of your body to the other, stop reading this review right now! For those that are curious, Mary Roach’s Gulp is the book for you. Roach humorously covers both silly and taboo topics: pet food taste-testers, internal deodorizers that keep bathroom odors away, resourceful prisoners who know just where to hide unbelievable amounts of contraband, and, yes, even the constipation that may have killed Elvis. For me, the chapter describing an American surgeon in 1825 that used a wounded trapper as his own lab rat stuck with me long after putting the book down. The patient had been shot in the abdomen, and the surgeon kept his wound open so he could observe the digestive process up close. Where else could the surgeon have an opportunity to lower food on a silk string directly into the stomach to see what happens to it? Sure, the book can be gross, but it’s also thought-provoking and funny. If you like Gulp, also try Roach’s Stiff: The Curious Lives of Human Cadavers.