Turning to the question about the 20th century, I suggest Jose Gironella's "The Cypresses Believe in God." This moving novel tells of one Spanish family in the 1930s and shows what happens when communist and fascist ideologies take precedence over God. Gironella understood the forces that push sane men toward murderous activities that prompt the other side to retaliate; those counter-activities then prompt the original perpetrators to see their action as justified.

The Spanish Civil War led to World War II, which led to Primo Levi's "Survival in Auschwitz," a gripping account of depravity that shows how 20th century totalitarians, believing man is merely an animal, tried to turn all men into animals. Instead of howling, Levi restrainedly wrote of life in hell, and his just-the-facts-ma'am story of survival amplifies the horror of the Holocaust.

Next comes "Witness" by Whittaker Chambers, the powerful autobiography and reflective meditation of a communist who became a Christian. To the scorn of the intellectual establishment, Chambers called himself "an involuntary witness to God's grace and to the fortifying power of faith." He also explained that he first came to believe in God by looking at his infant daughter's "intricate, perfect ears" after she had smeared porridge on her face: He realized that those ears "could have been created only by immense design," and "design presupposes God. ... At that moment, the finger of God was first laid upon my forehead."

I'll conclude on a hopeful note with Walker Percy's "The Second Coming." Of a half-dozen Percy novels that capture the God-driven hope and God-forsaken zaniness of contemporary American life, this is the most luminous in showing how humor beats alienation, faith overwhelms spiritual fatigue, and love for a woman can point a man to God. He concludes: "Am I crazy to want both, her and Him? No, not want, must have. And will have."