Since the proclamation of Redemptoris Missio, John Paul II's encyclical on the church's missionary mandate, the theme of new evangelization has come into focus as a key element of the Pope's spiritual teaching. In his lecture, Rev. Paul Philbert, O.P., Prior of the Dominican house of studies at St. Louis University, speaks of its various dimensions: re-evangelization, evangelization of culture, and evangelization through the effective forces of the Christian life of individuals within their natural contexts.