Dietrich Bonhoeffer was a double agent who plotted to assassinate Adolf Hitler in the Wolf’s Lair fortress. When the plot failed, Hitler made sure Bonhoeffer was executed in the final days before the German surrender. Today Bonhoeffer is hailed as a twentieth-century martyr. He voluntarily faced imprisonment and execution with determination and courage. But why did he do this? What values shaped his life, and where did these come from?