The Summa, an Introduction
St. Thomas Aquinas' massive work, the Summa Theologica was never completed. It has remained an open-ended volume of Orthodox explanation since the year 1273. Yet, Aquinas' impact and influence on our culture and even politics exist to this day. According to Timothy Renick..."[Aquinas'] views of the State supplied the model for the arguments of Thomas Jefferson in the Declaration of Independence. His views on justice and warfare and the status of noncombatants have been codified into international law and can be found in U.S. Military Handbooks...If you're an average American, Christian or not, you walk around spouting some of Aquinas' views - to some degree." T.Renick - Aquinas for Armchair Theologians, 2002.
The Summa Theologica presents a cycle explanation for God, Creation, Man, Christ, and the Sacraments, then returning back to God. It is Aquinas' summarization of virtually every doctrine of Christian theology practiced in his time. A student of Aristotelian philosophy, he intended to present this information to novices as a reference guide to all the primary teachings of Christianity.
Pope Leo XIII in 1879 declared Thomism to be the official theology of the Roman Catholic Church. This meant that any issues where the Pope or councils haven't definitively declared a position, the Catholic believer is instructed to refer to the teachings of Aquinas. They are the very definition of Catholic orthodoxy. Pope Leo's instructions regarding Aquinas' works still apply today, as emphatically restated in Pope John Paul II's encyclical - "Faith and Reason".
This document is meaningful in reflection, logic, reason and universal application for its timeless pursuit of Christian truth. There are numerous modern Summa resources, commentaries and advocates published on the WWW and in print that also illuminate the Summa for us to treasure and practice.