Dr. Hal Levison is a planetary scientist with the Southwest Research Institute in Boulder, CO. His work focuses on the long-term behavior of the solar system bodies and involves the development of large-scale numerical experiments. He is best known for his work on the early dynamical evolution of the outer Solar System and is an author of the most comprehensive model to date. Dr. Levison is also the co-author of SWIFT , which is a freely available software package for integrating orbits of solar system bodies.