Papal letters to the Universal Church or, in many cases, especially before Vatican II, to the Bishops in communion with the Holy See. Worthy of special attention besides Rerum Novarum (see previous post) are Quadragesimo Anno, Mater et Magistra, Pacem in Terris, Populorum Progressio, Laborum Exercens, Sollicitudo Rei Socialis, Centesimus Annus, Caritas in Veritate, Fides et Ratio, and Spe Salvi. As of this post, the Vatican has online the encyclicals of Leo XIII, Pius X, Benedict XV, Pius XI, Pius XII, John XXIII, Paul VI, John Paul II, Benedict XVI, and Francis. ISBN recommendation: 0-87650-259-1
A “compendium of all Catholic doctrine regarding both faith and morals”. An updated and systematic presention of “the teaching of Sacred Scripture, the living Tradition in the Church and the authentic Magisterium, as well as the spiritual heritage of the Fathers, Doctors and saints of the Church”. Promulgated by Pope John Paul II on 15 August 1997. Image links to Vatican translation. ISBN recommendation: 0385508190
Statement on the origin of life and evolution. Image links to EWTN translation. See also Appendix I, Joseph Cardinal Ratzinger: In the Beginning…, for a contemporary meditation on the Genesis creation accounts.