Quasars are now thought to have made critical impact on galaxy formation. Feedback from accretion onto supermassive black holes is implicated in establishing the black hole mass vs galaxy bulge correlations and in limiting the maximal mass of galaxies. In this talk, I will review the indirect evidence for quasar feedback as required by galaxy formation models. I will then present recent multi-wavelength observations of powerful quasar-driven winds and outflows on galaxy-wide scales. These data may provide direct observational evidence for one of the long-standing paradigms in galaxy formation.