Fifty years ago, when a lanky country preacher stepped onto the gang-ridden streets of New York City, most people thought he had gone over the edge. But David Wilkerson had faith that God was leading him and never looked back. Today his inner-city ministry, Teen Challenge, boasts residential and crisis counseling centers in more than seventy countries. Its Christian discipleship program has restored hope to tens of thousands of men and women with drug or alcohol addiction.