My research focuses mostly on supersymmetric higher dimensional quantum field theories. These are interesting both from the study of quantum field theory in general and due to their connection with string theory on one hand and theories in lower dimensions on the other. The last connection is given by compactifying the higher dimensional theory to lower dimensions, and has proved insightful, for example, in the study of four dimensional theories with 8 supercharges. I study all these aspects to better understand quantum field theories, in both lower and higher dimensions, and string theory.