In Pope Saint John XXIII’s Encyclical Mater et Magistra (May 15, 1961), the Holy Father sought to apply the Church’s social doctrine to numerous situations of the times, among them the issue of the common good. This paper first anchors the encyclical within the larger frame of world history at the time in which it was written, and then offers a brief overview of Mater et Magistra. In light of two specific themes in the encyclical, the individual person and socialization, a final remark highlights the notion of the common good.