| Observational evidence suggests that quasar activity plays an important role in regulating how galaxies and their nuclear supermassive black holes grow and co-evolve, despite their orders-of-magnitude difference in scale. In this talk, I will present a population of highly luminous dust-reddened quasars that may be the key to understanding this co-evolution. Red quasars are among the most intrinsically-luminous quasars in the Universe representing a short-lived phase in the lifetime of a quasar, during which their energy output (feedback) irrevocably impacts their host galaxies. I will present findings from several surveys that are uncovering this elusive population of quasars using various selection methods across the electromagnetic spectrum to probe a broad range of redshift and luminosity regimes. I will present results from detailed studies of selected subsamples that are beginning to shed light on the physics of feedback from quasars. I will discuss how reddened quasars fit into the larger picture of galaxy evolution which includes both mergers and secular growth. |