“This book aims to show how and why for Dietrich Bonhoeffer, from the conclusion of his student years in Berlin to his death on the Nazi gallows at Flossenbürg, the ecumenical movement was central to his concerns. Of course during these years he fulfilled several distinct roles: academic theologian and teacher, leading protagonist for the Confessing Church, pastor, seminary director and – most dramatically and controversially – willing participant in the German resistance and the conspiracy to overthrow Hitler. But it is his commitment and active involvement in the ecumenical movement that forms the most continuous thread of his life and activity, and links all his various engagements. Equally, the challenge that he laid down to that movement in his time remains a legacy which has still to be fully claimed by the ecumenical world today.”—from the Preface