Whatever you call them—crayfish, crawfish, or crawdads—these small crustaceans are a vital piece of the larger ecosystem, and though they're found nationwide, the American Southeast and Appalachia are among the most biodiverse places for these animals. Biologist and crayfish expert Zackary Graham takes readers on an informative journey, following crayfish from the coalfields of Central Appalachia to the spring-fed water of Northern California, and in roadside ditches everywhere in between. He discusses crayfish habitats—the muddier the better—anatomy, and coloration, which runs the gamut from dull grays to vivid blues, reds, and even bright white. Most important, Graham shows how necessary crayfish are to our ecosystem and rallies a call for protection as nearly 200 of the 400 unique species of crayfish in the United States are threatened by development, pollution, and other human-made factors. A love letter to a common crustacean, this book shows nature lovers that crayfish are diverse, important, and in need of our help.