The British epidemiologist McMichael takes his readers on a sweeping but accessible excursion covering the relationship between people and diseases since the beginning of civilization. He contrasts two perspectives on disease. The reductionist approach focuses on specific causes and specific remedies, disease by disease -- a perspective that has permitted increasing control of one disease after another during the past century. The ecological approach, in contrast, views disease and public health as part of a complex environment; disease agents respond to environmental changes, many of which are caused by humans as they grow wealthier, travel, urbanize, and change their diets and living conditions. The author urges that more attention be paid to the latter perspective, since humankind is leaving heavier footprints on the global environment than ever before and challenging societies' (admittedly considerable) powers of adaptation.