January 28 is the Feast of Saint Thomas Aquinas, widely considered the greatest theologian and philosopher of the Catholic Church. His works systematized the Truth of the Catholic Church and combined it with Greek wisdom and scholarship methods. In the several hundred years since Thomas, one of the most influential among the Church’s saints, preached, taught, and defended the Faith, his ideas and writings have become seminal to the Church.
Typically, people think of the multi-volume Summa Theologica when they think of Aquinas and immediately assume that trying to "get" St. Thomas is too difficult. Fortunately, there are plenty of resources that make Aquinas accessible to everyone.
Even during Aquinas's lifetime, people recognized that his writing wasn't accessible to everyone. His assistant, Brother Reginald, asked him to write a distilled version of the Summa for the average reader. Aquinas's Shorter Summa is the result.
A Shorter Summa was compiled by emininent philosopher, Peter Kreeft, to give the most essential passages from the Summa to the reader without a lot of time to plow through the whole collection.