""The Heart of the War: The War as a Challenge to Faith, Its Spiritual Causes, Its Call for a New Allegiance to the Prince of Peace"" is a book written by Julian Kennedy Smyth in 1914. The book explores the spiritual causes of World War I and the challenge it presents to faith. The author argues that the war is not just a physical conflict, but a spiritual one as well, and that it is a call for a new allegiance to the Prince of Peace, Jesus Christ...