David Garofalo works on general relativistic astrophysics via rotating Kerr black holes and how they influence their environments in active galactic nuclei (AGN) and X-ray binaries. Less than two decades ago, astronomers discovered the presence of supermassive black holes at the center of most galaxies, uncovering correlations between the mass of these black holes and various properties of the host galaxies in so-called scaling relations, showing that black hole formation and galaxy formation are tightly interconnected although in ways not yet well understood. David and colleagues have recently suggested that the spin of these supermassive black holes might be more fundamental than their mass in determining the kinds of outflows produced in AGN, which in turn determine how the galaxies themselves evolve in time. They seem to be uncovering that general relativity is a fundamental driver of galaxy evolution.