The matter of the legacy of Dietrich Bonhoeffer is at once straightforward and immensely complicated. About the man there is no question. Whatever Bonhoeffer’s flaws—and Charles Marsh’s masterly and comprehensive new biography Strange Glory reveals that there were more than is commonly supposed—the witness of his breathtakingly courageous opposition to Adolf Hitler’s Third Reich leaves criticism disarmed.1 In the one great challenge of his life, he was magnificent. He behaved the way that the rest of us, in our most hopeful moments, like to imagine we would.

But Bonhoeffer is known to history not simply as a victim of N ...