Richard Lenski is the John Hannah Distinguished Professor of Microbial Ecology at Michigan State University. He studies the genetic mechanisms and ecological processes that produce evolution. In an experiment started in 1988, he and his team have studied 12 populations of bacteria as they evolve in the laboratory for over 65,000 generations, providing insights into the process of adaptation by natural selection, the dynamics of genome evolution, and the origin of new functions. He is a past President of the Society for the Study of Evolution, and he was a member of the National Research Council committee that reviewed the scientific approaches used in the FBI’s investigation of the 2001 anthrax attacks. He helped start the BEACON Center, which brings together biologists, computer scientists, and engineers to harness and illuminate the power of evolution in action. He is a fellow of the American Academy of Arts and Sciences and a member of the National Academy of Sciences.