This weekend marks the 80th anniversary of US troops capturing the Ludendorff Railroad Bridge, one of the last intact bridges across the Rhine. Although fierce fighting lay ahead, it marked a decisive turning point in the war against Nazi Germany. Tragically, just weeks later in early April, Dietrich Bonhoeffer, a 39-year-old German pastor and theologian who had opposed Hitler, was executed by hanging. By early May, Germany had signed an unconditional surrender. Bonhoeffer remains a figure of fascination to many. How did one relatively young man manage to resist the madness sweeping his country? How did a committed pacifist end...