He graduated in philosophy and a doctorate in theology (University of Chicago, 1973) with a thesis on the Roman Catholic modernism of the early twentieth century. He was professor of historical and systematic theology at the Weston Jesuit School of Theology (Cambridge, Massachusetts), until, following the publication of this book was withdrawn permission to teach Catholic theology. He currently teaches teaching at Union Theological Seminary in New York; He has also been visiting professor at Lima, Nairobi, Paris and Pune (India). His extensive published (seven books and over a hundred articles) work deals with issues such as the nature of theology as a discipline, Christology, ecclesiology, grace or liberation theology. His most recent books are the two volumes of Christian Community in History (2004 and 2005) and The Future of Christology (2005).