We use high magnetic fields and low temperatures to explore superconductors, correlated metals, spin liquids, and topological semimetals. High fields are a versatile and `clean’ tuning parameter that can be used to probe the electronic structure of materials, suppress or enhance competing orders such as superconductivity, or induce phase transitions to new states of matter. We have in-house capabilities up to 20 tesla steady-state and 35 tesla pulsed-field, and we use fields up to 100 Tesla available at user facilities around the world. Below are just a few examples of the projects we are working on, and the techniques we currently use and are developing.