Catholic Social Teaching (CST), or the Social Doctrine of the Church, is frequently mentioned but seldom understood and applied aright. To become intimately acquainted with CST, there is no substitute for reading the writings of the popes, who, from Leo XIII onwards, are the authentic sources for the subject, and whose ideas have left a permanent mark on Catholic and secular thought alike. CST is neither platitudinous social commentary nor assertions of economic utopianism. Rather, it takes seriously man's identity as both a "political animal" and a being created in God's image and likeness-one who matures within the family, inherits a culture, and participates in society for his own good and the good of all. CST therefore grapples with fundamental questions of human existence, and enunciates the principles that guide virtuous human activity and sustain a flourishing society. This collection, edited by Peter A. Kwasniewski, introduces the reader to the full breadth and depth of CST with a carefully chosen array of documents from Pope Pius IX to Pope Benedict XVI. Kwasniewski has, moreover, corrected hundreds of typographical errors, incorrect citations, missing phrases, and poor translations that are found in the standard editions. The result is a book excellently suited to bring its readers to an ever-greater appreciation of the nobility of man; the lofty purpose of our freedom, which finds its origin and its fulfillment in the truth that sets us free; and the Kingship of Our Lord Jesus Christ, who took on our human nature to share with us His divinity.