There are a suite of unsolved problems in astronomy – from supermassive black hole formation, to binary star evolution, to cosmology – that will remain stubbornly elusive even with the next generation of electromagnetic observations. Fortunately, LISA, a space-based gravitational wave observatory set to launch in 2034, will revolutionize our field by providing data that is complementary to electromagnetic observations as well as data in regimes that are electromagnetically dark. This talk will touch on our current understanding of strong gravitational wave sources, such as supermassive black hole mergers, and will outline the theoretical, computational and observational work needed to make the most of LISA observations.