The Large Catechism

Martin Luther was one of the most influential men of the last millennium, and the man most responsible for the Reformation that split the Catholic Church in the 16th century. A German theologian, Luther wrote at length criticizing the Church and sparked the Reformation, all while being one of the most read authors on the continent in his lifetime. His teachings included important departures from Church dogma, including the claim that absolution of sin could not be purchased. Today his 99 Theses are among the most famous works in the world.

Luther's Large Catechism is a large work on his theological beliefs, and it's broken down into 5 parts and a preface. The Large Catechism discusses everything from the Creed to the 10 Commandments and prayer.