I am a theoretical physicist working primarily on dark matter and cosmology, and with broad interests ranging from particle physics to galaxy formation. I am an expert in axion physics, recognised worldwide. In my work, I carry out analytic calculations in cosmological structure formation and in classical field theory. I maintain the public code axionCAMB, and work regularly with data from cosmological surveys using Bayesian techniques. My formal training is in theoretical particle physics, and I have performed technical calculations in quantum field theory and string theory.