Marc Kamionkowski is a theoretical physicist who specializes in cosmology. He earned his Ph.D. in physics at the University of Chicago, followed by postdoctoral study at the Institute for Advanced Study in Princeton and faculty positions at Columbia University, where from 2006 to 2011 he was the Robinson Professor of Theoretical Physics and Astrophysics. In 2011 he joined the faculty at Johns Hopkins. Kamionkowski’s most significant research contributions are in the theory of dark matter, dark energy and the cosmic microwave background, but he has also worked in other areas of astrophysics and early-Universe and physical cosmology. His recent honors include the E. O. Lawrence Award for Physics (2006), an American Physical Society Fellowship (2008) and a Miller Visiting Research Professorship at Berkeley (2010). He was elected to the American Academy of Arts and Sciences in 2013 and in 2014 named a Simons Foundation Investigator. Editor-in-chief and astrophysics and cosmology editor for Physics Reports, he has also served as an editor of the Journal of High Energy Physics and the Journal of Cosmology and Astroparticle Physics. In addition to his service on national committees and external advisory panels, he is a member and trustee at the Aspen Center for Physics.