Richard Shaull (1919–2002) was the Henry Winters Luce Professor of Ecumenics Emeritus at Princeton Theological Seminary. For many years he was a Presbyterian missionary and professor at theological seminaries in Brazil. His previous books include Liberation and Change (with Gustavo Gutierrez); Naming the Idols; and The Reformation and Liberation Theology, as well as a number of volumes in Spanish and Portuguese.
Waldo Cesar is a Brazilian sociologist and Founder of the Institute for the Study of Religion in Rio de Janeiro, where he spent many years as a member of the research team. He is the author of a number of books, including For a New Policy of Aid and The Church's Role as Agent of Peace and Development: Case Study: Brazil. He is now retired.