Mark Bautz conducts observational research on clusters of galaxies and develops instrumentation, mainly for high-energy astrophysics. Recently, his observational work has focused on the astrophysics of a new collection–clusters detected in a Sunyaev-Zeldovich survey performed by the South Pole Telescope, and on hitherto unexplored regions at the outskirts of clusters. Mark is also working with groups at MKI and at MIT Lincoln Laboratory on next-generation active pixel X-ray imaging detectors.