This collection includes the most important books by the medieval clergyman and philosopher St. Anselm and one work of his opponent which is necessary to for a complete understanding of the matter of discussion. The first book from the sequence, Monologion was created back in 1075. It's first title was A Monologue on the Reason for Faith. In this work, Anselm states that anyone should be able to convince themselves of the existence of God through reason alone if they are intelligent. If there is something good, there can be things greater and better. Thus, there should be one thing that is supremely good and supremely great. It should be supreme among all other existing things.In Proslogion, Anselm develops his arguments previously presented in Monologion. This work is most famous for formulation of the ontological argument for the existence of God. This argument is also known to the Scholastics as «Anselm's argument» (ratio Anselmi). According to it, even atheists can imagine a greatest being, having such attributes that nothing greater could exist. But if such a perfect being can be imagined as not existing, another perfect being can be imagined as existing, or having an attribute of existence. Thus, such a perfect being should exist. The collection also contains the book that wasn't written by Anselm but is tightly connected with his Proslogion. That is In Behalf of The Fool by Gaunilo. He was a Benedictine monk in the middle ages who contradicted St. Anselm's ontological argument. Gaunilo was an empiricist and believed that a human experience can be acquired only through senses. He stated that St. Anselm was wrong because the logic of the same kind would force one to conclude many things existed which certainly didn't. In Cur Deus Homo, that is often translated like Why God Was A Man, Anselm speculates on the topic of atonement, that is the salvation of humans through the crucifixion of Jesus Crist. He writes that thought the history the humans made too many sins for an adequate restitution and to save the humanity, deemed for devastation, God sent Jesus. Jesus is a sinless being both divine and human, that made him able to pay for the sins of humankind by his death. Cur Deus Homo is considered one of the greatest works of Anselm and it had an immense importance in the development of the further church doctrine.