Leslie Orgel was a London-born senior fellow and research professor at the Salk Institute for Biological Studies, San Diego, whose research focused on the chemical evolution of life. Orgel, together with Carl Woese and Francis Crick, was among the original group of scientists in the 1960s to suggest that RNA rather than DNA acted as the first replicative molecule, and continues to explore possible modes of protobiological evolution within the "RNA world" scenario today. In 1973, he and Crick put forward the remarkable idea of directed panspermia. Orgel was a member of the Viking molecular analysis team and, in 1998, chaired the Task Group on Sample Return from Small Solar System Bodies, a committee convened to make recommendations for protocols to avoid back-contamination. After earning a BA (1949) and PhD (1951) in chemistry from Oxford, Orgel became a reader in chemistry at Cambridge and subsequently the assistant director of research at Cambridge's Theoretical Chemistry Department (1955–1963). From 1964, he was at the Salk Institute and also served as adjunct professor at the University of California, San Diego.