Pigs are everywhere in United States history. They cleared frontiers and built cities (notably Cincinnati, once known as Porkopolis), served as an early form of welfare, and were at the center of two nineteenth-century "pig wars." American pork fed the hemisphere; lard literally greased the wheels of capitalism. J. L. Anderson has written an ambitious history of pigs and pig products from the Columbian exchange to the present, emphasizing critical...