St. Thomas Aquinas’
Summa Theologica

Saint Thomas Aquinas (1225 – 1274) was a Dominican friar and Doctor of the Church known as the Doctor Angelicus, and is the father of a school of thought (encompassing both theology and philosophy) known as Thomism.  He was an immensely influential philosopher, theologian, and jurist in the tradition of scholasticism. Aquinas’s masterwork Summa Theologica (1265–1274) is considered to be the pinnacle of scholastic, medieval, and Christian philosophy.  
The Summa Theologica (transl. ’Summary of Theology’) is the best-known work of Thomas Aquinas. It is a compendium of all of the main theological teachings of the Catholic Church, intended to be an instructional guide for theology students. Presenting the reasoning for almost all points of Christian theology in the West, topics of the Summa follow the following cycle: God; Creation, Man; Man’s purpose; Christ; the Sacraments; and back to God.