Samuel Gregg provides an insightful, cogent, and thorough analysis of the issues surrounding developments in Catholic social teaching during the pontificate of John Paul II. He compares the treatment in John Paul’s social encyclicals of three topics-industrial relations, capitalism, and the relations between developed and developing countries-with the handling of these matters in the social teachings of the Second Vatican Council and Paul VI. Through the application of a comparative exegetical approach to the relevant texts, it becomes apparent that John Paul’s development of the teaching derives from several sources. Within this analysis, Gregg considers a more specific and less widely examined issue: the extent to which the development in Catholic social thought has been influenced by the writings of Karol Wojtyla before he became pope in 1978. In addition to revealing an openness to certain modern philosophical insights and expressing a range of views about the modern world, these writings elaborate a distinctive anthropology of man as the conscious subject of moral acts.