At the end of the Permian period, some 250 million years ago, 90% of all species were wiped out. Numerous hypotheses about the causes have been presented, including impact by an asteroid, but the consensus now focuses on massive volcanic eruption in Siberia. The immediate killers were linked aspects of substantial global warming – acid rain, increased temperature, aridity on land, and ocean anoxia. Professor Michael Benton’s work in Russia has pieced together the first steps in what is known as ‘The Killing Model’. In his Hoboken Lecture he will explain the mystery of the greatest mass extinction ever.