Professor Christopher Reynolds has broad interests in observational and theoretical high-energy astrophysics. Much of his work and that by his group centres on the astrophysics of black holes and the role that they play in the Universe, addressing four specific themes -- observational probes of relativistic physics close to black holes, black holes as probes of physics beyond the Standard Model, theoretical studies of accretion disks, and theoretical studies of the influence that supermassive black holes have on galactic-scale structure formation.