Ven. Bhikkhu Bodhi, a senior American Buddhist monk and distinguished scholar and translator, explores the nature of the social activism that has become a more visible aspect of Buddhist practice in recent decades. The author argues that while social engagement is deeply rooted in classical Buddhism, the scope and manner of social engagement have undergone a shift. The author reviews the history of Buddhist thinking on this topic and relates this history to gradual changes in society in general. This article was presented as the Eighth Annual Hsüan Hua (Xuanhua) Memorial Lecture in Berkeley, California, in April 2009. (A companion lecture given by Dr. Raoul Birnbaum follows Bhikkhu Bodhi's article.)