Quasar Hosts and the Black Hole-Spheroid Connection

I review our current understanding of the structures and ages of the host galaxies of quasars, and the masses of their central black holes. At low redshift, due largely to the impact of the Hubble Space Telescope, there is now compelling evidence that the hosts of quasars with M_V 2). Moreover, there is now good evidence that certain ultraviolet quasar emission lines can provide robust estimates of black hole masses from the observed optical spectra of quasars out to z > 2, and perhaps even at z > 4. By combining such information with deep, high-resolution infrared imaging of high-redshift quasar hosts on 8-m class telescopes, there is now a real prospect of clarifying the evolution of the black hole spheroid connection over cosmological time scales