Throughout the history of the church and the Scriptures, it seems that people are always trying to accommodate the eternal truths of God’s Word to the Spirit of the Age. Following World War I, Harry Emerson Fosdick popularized modern liberalism in America. J. Gresham Machen led the Evangelical response, arguing for the centrality of doctrine in defining Christianity. The battle between these two men would shape American Christianity in the twentieth century. This book examines the apologetic and philosophical concerns behind the modern liberal movement and the strengths and weaknesses of the Evangelical position, paying particular attention to the lasting legacy of Machen. Since the same questions that fueled the modern liberal movement continue to circulate and influence generations of believers and non-believers, it seems that the church must be more proactive in addressing these questions and the doubts that undergird them.