In April 1862 a Union force under Ulysses S. Grant and a Confederate army led by Albert Sidney Johnston clashed in southwestern Tennessee in the Battle of Shiloh. Precisely 150 years later, military historian Gregory S. Hospodor discusses what was to that point the bloodiest fighting of the Civil War and explains how it brought home to both sides the grim reality of the conflict. Hospodor is an associate professor of military history at the United States Army Command and General Staff College, Fort Leavenworth, Kansas, where he was named teacher of the year for 2011.