Rich Leonardi asks an excellent question about the authority of the recent "Compendium of the Social Doctrine of the Church" issued by the Pontifical Council for Justice and Peace.
The Holy Father Pope John Paul II asked the Pontifical Council for Justice and Peace to produce this compendium. The work was begun by the late and venerable Cardinal Francois-Xavier Nguyen Van Thuan from Vietnam who was cruelly imprisoned for many years by the Vietnamese communists.
Most of the Compendium consists of quotations from existing Church documents - Council decisions, Papal encyclicals and speeches, the Catechism of the Catholic Church, other Church documents, and the odd writings of a Saint (eg from the Summa Theologica of St Thomas Aquinas). It's authority rests directly on the documents it draws upon.
In this sense, the Compendium is similar to the Catechism of the Catholic Church which was also drawn up by Papal request and quotes extensively from existing Church documents.
The Compendium doesn't really contain anything new - it just draws together existing church teaching into a single book.
See
Presentation of Compendium of Church's Social Doctrine, "A Text That Had No Precedent"
Compendium of Church's Social Doctrine Is Due Out
Cardinal Says Document Unprecedented In Church History
