Dr. Phillips received his Ph.D. in astronomy from the University of California at Santa Cruz in 1977, and spent many years working at the Cerro Tololo Inter-American Observatory in Chile before moving to the Observatories of the Carnegie Institute of Washington in 1998. He has worked in a wide variety of astronomical fields during his career, but is most celebrated for his seminal work in establishing the utility of exploding stars -- ``supernovae'' -- as cosmological distance indicators. In the 1990s, Dr. Phillips worked as part of the ``High-z Supernova Search Team'', which used these cosmological beacons to trace the expansion history of the universe very far back in time, deep into the regime where gravity was expected to have imprinted its decelerating signature. Instead, the data revealed a universe that is presently accelerating in its expansion rate, a finding heralded by Science Magazine as the ``Scientific Breakthrough of the Year'' in 1998, and one that has since survived intense scrutiny and complementary experimental checks. In 2007, Dr. Phillips shared the Cosmology Prize of the Peter and Patricia Gruber Foundation for his role in this discovery.