"This publication highlights important medical innovations and improvements gained from the deadliest day in US history, the Battle of Antietam. This pivotal US Civil War battle helped shape future combat medical readiness practices in the US Army. The Battle of Antietam provides important lessons in battlefield tactics, leadership, command and control, communications, and unit training that improve the nation's readiness to bring combat power to commanders in the field of battle. It was during this battle that the US Army solidified its emerging plan to decisively combat battlefield mortality, which marked the beginning of true combat readiness through medicine. This publication is applicable to the entire range of health care in the Department of Defense and can serve as a valuable learning aid for a variety of military and civilian medical professionals. This study can used in conjunction with the US Army Center of Military History's Staff Ride Guide: Battle of Antietam or it can be used separately as a focused analysis of military medicine"-- Provided by publisher.