Dietrich Bonhoeffer was only thirty-nine when he was executed by the Nazis in 1945, yet his influence on Christian life has been enormous. His passionate, theology-based opposition to Nazism made him a leader, along with Karl Barth, in Germany's Confessing Church. Bonhoeffer is embraced by both liberal and conservative Christians, and the integrity of his faith and life have led believers everywhere to recognize him as the one theologian of his...