My research focuses on theoretical gravitational physics, black holes, and mathematical relativity. I am a recognized expert on hidden symmetries, separability, and integrability of field equations in curved spacetime. I am one of the founders of a new subdiscipline of black hole physics known as black hole chemistry. In the last couple of years I have pushed forward our understanding of exotic black hole spacetimes, studied the interaction of ultralight bosons with rotating black holes, proposed a new theory of gravity, studied the gravitational wave production by a coalescence of dilatonic black holes, and shown how to derive consistent horizon thermodynamics from the Einstein equation of state.