Many landmarks of environmental history share a connection with a single molecule: DDT. During and after the Second World War, it was broadcast into the environment at a scale that far surpassed the applications of any prior chemical. The public met this mass spraying of DDT with enthusiasm, as the war proved it to be highly effective against the vectors of malaria, yellow fever, typhus, and other insect-borne diseases. But these public health successes were short-lived as insects quickly evolved resistance. Nevertheless, DDT use skyrocketed around the world, especially in agriculture. It was also used on a massive scale in forestry, in the Sisyphean fight against invasive insects, and in the home, where clever companies impregnated all manner of commercial products with DDT, ranging from bug bombs to house paint to wallpaper for the nursery. Due primarily to its massive impact on the environment, but also to effects on human health, a backlash ensued, driven most forcefully by Rachel Carson’s 1962 book Silent Spring. The chemical was banned throughout the world in the 1970s and 80s, and yet its story continued. With us to unravel this complex tale, and its relation to science denial and corporate malfeasance, is Elena Conis. Elena is a historian of medicine and an Associate Professor in the Graduate School of Journalism and Department of History at the University of California, Berkeley. Her research focuses on scientific controversies, science denial, and public understanding of science. She is the author of Vaccine Nation: America’s Changing Relationship with Immunization, and a co-editor of Pink and Blue: Gender, Culture, and the Health of Children. Today we discuss her most recent book, How to Sell a Poison: The Rise, Fall, and Toxic Return of DDT.