Astrophysicist John Chambers, a leader in research on the formation of the Earth and terrestrial planets and a former research scientist at the SETI Institute, joined the staff of DTM on April 19. Chambers brings considerable experience in the numerical simulation of planetary accretion, including work based on an approach developed by DTM's George Wetherill, who helped to pioneer the field. Chambers uses these models to understand such problems as the influence of the giant planets on inner planet formation, the origin of the heavy bombardment of the inner solar system, and the sources of water and other volatiles on the Earth and the terrestrial planets. In the search for extrasolar planets and, more specifically, habitable worlds akin to Earth, Chambers' work provides an important tool for determining the likelihood of such Earth-like planets as well as the conditions necessary for their formation and orbital stability. With Carnegie Institution's role as a lead team in the NASA Astrobiology Institute, the addition of Chambers to the DTM staff will enrich the group's work in astrobiology as well as in astrophysics and planetary science.