Kaplan has spent his life traveling the globe exploring oceans and jungles, and incidentally acquiring parasites in his gut. Here, he leads readers on an unforgettable journey into the bizarre yet oddly beautiful world of parasites. In a narrative that is by turns frightening, disgusting, and laugh-out-loud funny, Kaplan describes how drinking contaminated water can cause a three-foot-long worm to burst from your arm; how he gave birth to a parasite the size and thickness of a pencil while working in Israel; why you should never wave a dead snake in front of your privates; and why fleas are attracted to his wife. Kaplan tells stories about leeches feasting on soldiers in Vietnam; sea cucumbers with teeth in their anuses that seem to encourage the entry of symbiotic fish; the habits of parasites that cause dysentery, river blindness, and other horrifying diseases--and much, much more. Along the way, he explains the underlying science, including parasite evolution and host-parasite physiology.