Leonardo Boff was born in Brazil in 1938 and received a doctorate from the University of Munich in Germany in 1970. For the following twenty years, he worked as Professor of Theology at the Franciscan School for Philosophy and Theology in Petropolis, Brazil. During the 1970s, he and Gustavo Gutierrez helped to define liberation theology. Since 1993 he has been a professor at the State University of Rio de Janeiro, where he is now Emeritus Professor of Ethics, Philosophy of Religion, and Ecology. He is also a member of the international Earth Charter Commission. Boff is the author of more than seventy books, including Saint Joseph: The Father of Jesus in a Fatherless Society (Cascade Books, 2009) and Virtues: For Another Possible World (Cascade Books, 2010). In 2001 he was awarded the Right Livelihood Award (which is considered to be the "alternative" Nobel Prize) by the Swedish Parliament.
Robert Barr, S.J., completed work on a doctorate in patristic theology at the Institut Catholique in Paris. He has authored a wide range of articles in various American and European scholarly reviews; included among these are studies on the saving significance of Christ's resurrection, on Russian ecclesiology, and on St. Augustine's 'City of God'.