ESG investing has become a very powerful force in institutional investing. Yet very little research exists on the subject. In this paper, we first highlight the key statutory changes that have created tailwinds for ESG investing. We then explain the approaches to this investment philosophy. We discuss the challenges investors face in using ESG metrics, and correlate ESG investment and environmental impact by comparing sustainable investment increases with trends in carbon emissions. Finally, we conclude that ESG investments generate alpha for the asset managers.