The German theologian Dietrich Bonhoeffer understood Western civilization to be approaching a completely religionless age to which Christians must respond and adapt. This book explores Bonhoeffers own response to this challengehis concept of a religionless Christianityand its place in his broader theology. It does this, first, by situating the concept in a present-day Western socio-historical context. It then considers Bonhoeffers understanding and critique of religion, before examining the religionless Christianity of his final months in the light of his earlier Christ-centred theology. The place of mystery, paradox, and wholeness in Bonhoeffers thinking is also given careful attention, and non-religious interpretation is taken seriously as an ongoing task. The book aspires to present religionless Christianity as a lucid and persuasive contemporary theology; and does this always in the presence of the question which inspired Bonhoeffers theological journey from its academic beginnings to its very deliberately lived endthe question Who is Jesus Christ?