Paul Müller was an industrial chemist who discovered that dichlorodiphenyltrichloroethane (DDT) could be used as an insecticide. This was the first insecticide that could actually target insects; in small doses it was not toxic to humans and yet it was stable enough to remain effective over a period of months. When DDT was introduced in 1942, the effects it would have on the environment were not well understood. It was widely hailed, in particular for its ability to reduce the incidence of tropical diseases by reducing insect populations. For his work with DDT and the role his discovery played in the fight against diseases such as typhus and malaria, Müller was awarded the 1948 Nobel Prize in medicine or physiology.

Paul Hermann Müller was born in Olten, Switzerland, on January 12, 1899, to Gottlieb and Fanny Leypoldt Müller. His father was an official on...