Catholic social teaching (CST) refers to the corpus of authoritative ecclesiastical teaching, usually in the form of papal encyclicals, on social matters, beginning with Pope Leo XIII's Rerum Novarum (1891) and running through Pope Francis. CST is not a social science and its texts are not pragmatic primers for social activists. It is a normative exercise of Church teaching, a kind of comprehensive applied - although far from systematic - social moral theology. This volume is a scholarly engagement with this 130-year-old documentary tradition. Its twenty-three essays aim to provide a constructive, historically sophisticated, critical exegesis of all the major (and some of the minor) documents of CST. The volume's appeal is not limited to Catholics, or even just to those who embrace, or who are seriously interested in, Christianity. Its appeal is to any scholar interested in the history or content of modern CST.