Economic development entails moving workers out of traditional agriculture and into more productive activities, thus lowering the share of the labor force in agriculture, which is over 80 percent in the poorest countries and under 2 percent in the richest. This process has taken place in country after country, beginning in the United Kingdom in the eighteenth century. This well-researched book usefully provides a history of agriculture, which is underappreciated when it is not being romanticized in rich urbanized societies, from 1800 to the present. The basic story involves changing methods of production -- more irrigation, greater fertilization, and better seeds -- which result in better nutrition and higher average standards of living with less effort throughout the world. Property rights, contractual obligations between tillers and landowners, and, in the twentieth century, state policies toward agriculture have varied enormously from country to country and are shown to have had consequential effects on agricultural output. The collectivization of agriculture in communist countries was noteworthy for its gross inefficiencies, which were sometimes obscured for a period by massive applications of capital.