Over the past five decades, immigration has dramatically changed the religious landscape of the United States. Today, the encounter of people of different religious traditions takes place in our own cities and neighborhoods. In 1991, the Pluralism Project at Harvard University began a pioneering study of America's changing religious landscape. Through an expanding network of affiliates, we document the contours of our multi-religious society, explore new forms of interfaith engagement, study the impact of religious diversity in civic life, and contextualize these findings within a global framework.