Although snails are not the first animals that come to mind when venoms are mentioned, there are in fact a large number (~10,000 species) of different venomous predatory snails. The most intensively studied of these are the cone snails (Conus), which have a large number of peptide neurotoxins present in their venoms. Some cone snail venoms are lethal to man; one species causes a 70% fatality rate. How these venoms have been used to understand the nervous system, and how the characterization of the components of the venom have led to the development of drugs is the subject of Olivera’s lecture. The biology of the snails, including how some cone snails catch fish, is correlated with the venom chemistry.