Author, Professor at University of Wisconsin In 1941 the Food and Drug Administration approved the use of diethylstilbestrol (DES), the first synthetic chemical to be marketed as an estrogen and one of the first to be identified as a hormone disruptor—a chemical that mimics hormones. Its residues, and those of other chemicals, in the American food supply are changing the internal ecosystems of human, livestock, and wildlife bodies in increasingly troubling ways. In this gripping exploration that forms her new book, Nancy Langston shows how these chemicals have penetrated into every aspect of our bodies and ecosystems. Nancy Langston, a professor in the Department of Forest and Wildlife Ecology with a joint appointment in the Nelson Institute for Environmental Studies at the University of Wisconsin, Madison, was president of the American Society for Environmental History in 2007–9.