I am an extragalactic observer. I mainly work on a range of topics centered on quasars and supermassive black holes (SMBHs), to understand the physics and evolution of these exotic objects in the cosmological context. Specifically, I work on the large-scale structure traced by quasars, the demography of SMBHs as a function of cosmic time, the phenomenology and physics of black hole accretion, and the co-evolution of black holes and host galaxies. I use multi-wavelength survey data and dedicated observing programs to carry out these studies.