My research is focused on non-perturbative aspects of quantum field theory. I am especially interested in defects and their role in duality, supersymmetric gauge theory, and their mathematical applications. My recent work has centered on extracting exact results using supersymmetric localization. Some of the most challenging aspects of strongly coupled quantum field theory, for which we have few if any analytic tools, such as finding the spectrum, computing correlation functions, and figuring out the low energy behavior, can be greatly simplified using supersymmetry and localization.