This series of three talks was the seedbed for the book I later co-authored with Patrick Madrid titled, The Godless Delusion: A Catholic Challenge to Modern Atheism. In it I take an approach to the question of how to evangelize those who doubt or deny the existence of God that is a little different than what you may have heard before, but that I think is very powerful. Rather than presenting purely abstract arguments for the existence of God, what I do is show some of the ways in which the atheist is at war within himself. He can say there is no God and that the universe consists entirely of brute physical particles, but he cannot square this view of things with what he knows to be true about himself. He cannot account for even the most basic and fundamental aspects of his experience as a human person -- his experience of morality, freedom, rationality -- on the basis of what he claims to be true of the universe in which we live and move and have our being.