In 1937, on the threshold of Nazi Germany's war on the world, Dietrich Bonhoeffer wrote what turned out to be one of the most influential books of the century, The Cost of Discipleship. In it, he challenged the flabby faith and compromises of German Christians, famously writing, When Christ calls a man he bids him come and die. Now, seventy-three years after the book was first published, Jon Walker writes Costly Grace: A Contemporary View of Bonhoeffer's The Cost of Discipleship. Walker brings to a new generation the timeless message of Bonhoeffer against the background of today's political upheaval and societal change and what it means to those who claim to follow Christ's teachings. Christianity Today named Bonhoeffer's book one of the ten most influential books of the twentieth century, but although the book still has a loyal readership, it has not been adequately viewed through the eyes of the twenty-first century, until now. In Costly Grace, Walker, who worked with Rick Warren for several years and recently authored Growing with Purpose (Zondervan, 2009), writes a book that will challenge contemporary teachings and lifestyles. Grace is a foundational doctrine for Christians, yet it is one of the most misunderstood. Bonhoeffer watched as many used the doctrine of grace as an excuse to do whatever they wanted, and in response, he wrote his classic work on what it truly means to follow Jesus. We cheapen grace, he declared, when we use it to compromise our behavior or to lower the standards of God's Word. In a modern retelling of this Christian classic, Walker explains what Bonhoeffer meant when he taught that grace is free but will cost us everything.