Allen is an author, educator, and historian. He has written five books: The Analyst; Teacher of Civil War Generals; Your Affectionate Father, Charles F. Smith; Charles A. Marvin - "One Year. Six Months, and Eleven Days", and Preparing for Disunion. Allen's latest book, Ebenezer Allen - Statesman, Entrepreneur, and Spy is scheduled for release in August 2020. He teaches classes on the American Civil War at Collin College. He has visited more than 130 Civil War sites and shared his over 4,000 photographs on Civil War Journeys. He wrote posts about the Civil War on the Salient Points blog.