Much of my research has been motivated by the electroweak hierarchy problem and the strong CP problem. I have worked on the physics of the Higgs boson, particularly in the context of supersymmetric solutions to the hierarchy problem; the cosmology of axion solutions to the strong CP problem and other axion-like dark matter candidates; and the experimental probes of other mechanisms that could address strong CP. I am also interested in more theoretical aspects of quantum field theory, particularly regarding nonperturbative phenomena in gauge theories, and in constraining effective field theories with ultraviolet consistency conditions.