Lester Salamon's insightful identification and scholarly analysis of a hitherto invisible revolution underway on the frontiers of philanthropy and social investing is possibly the most exciting and fresh lens we have had to date with which to look at an important set of new developments in the social-purpose arena that up to this point have largely been neglected. Salamon's work should help usher in a new era of social-purpose finance, the end result of which may be new alliances among foundations, governments, and the managers of private investment capital to leverage substantial new resources into efforts to solve problems of poverty, ill-health, and environmental degradation the world over. New Frontiers of Philanthropy is truly cutting edge research that should be read and disseminated widely.