This is my third Roach book, after Stiff (about corpses) and Packing for Mars (on space exploration). This one is about the digestive tract. Yes, really. All the books I've read by her are very entertaining and had me smiling throughout--though this was the first one (on page 229) that made me laugh out loud--a rare distinction and why this one is getting that fifth star. Roach dares to ask all the questions you wish you thought of--or wished you weren't too squeamish to ask. She'll tell you in this one all about the science of poop, farts, spit and more. Her last chapter is called "The Ick Factor." She says in her introduction she wants the reader "to say 'I thought this would be gross, but its really interesting.' Okay, and maybe a little gross." Mission accomplished. Along the way though you do learn a lot of esoterica, and some useful medical facts, too. Such as the basic tastes are sweet, bitter, salty, sour--and umami (brothy). I thought it was only the first four. Did you know that "catfish are basically swimming tongues"? That Sudanese use a condiment of fermented cow dung? That"laundry detergent is essentially a digestive tract in a box." That an effective medical treatment is to introduce useful microorganisms by transplanting them using another's feces? Roach also takes a shot at debunking food fads such as probiotic foods, gluten-free and the fetish for fiber. (Good luck on that--food myths are immortal.) Definitely a great read--just not while you're eating.