Unfurl Those Colors! provides an operational study of the Army of the Potomac during the pivotal Battle of Antietam on September 17, 1862, illuminating in details that will fascinate scholars and armchair generals alike US army commander George B. McClellan’s command decisions and how those decisions were carried out in the middle and lower ranks of the Second Army Corps. Armstrong offers the most comprehensive account yet of the Second Army Corps’s fight at Antietam, including Sedgwick’s division in the West Woods and French’s and Richardson’s divisions at Bloody Land. He offers a fresh reappraisal of the leadership of Bostonian Edwin V. “Bull Head” Sumner as the only federal corps commander who doggedly and accurately carried out McClellan’s battle plan and effectively directed the battle on the Federal right. Many esteemed Civil War historians consider Antietam a watershed moment in the Civil War, a crucial success after which Abraham Lincoln was emboldened to issue the Emancipation Proclamation. Unfurl Those Colors! offers a vital examination of the operational fabric of the Army of the Potomac’s leadership and command in one of the most important days in American history. “Military historians will find plenty of useful material in Unfurl Those Colors! Armstrong’s book serves as a model for a new style of Civil War campaign history, as it integrates traditional tactical minutiae with social histories of the different Union regiments and biographies of the different  battlefield leaders in the Second Corps. The tactical material is not terribly new, but this book will serve as a useful tool for military staff rides, battlefield enthusiasts, and historians of Civil War combat.” —H-Net Reviews "Fully complementing each other, the maps and battle narratives of the companion studies  Unfurl Those Colors!  and  Opposing the Second Corps at Antietam  together comprise the literature's clearest and most complete tactical history of the West Woods and Sunken Road phases of the Antietam battle. These volumes should be regarded as essential components of the 1862 Maryland Campaign bookshelf." — Civil War Books and Authors “ Unfurl Those Colors! is a very important contribution to the field of Civil War and military history. While a number of significant books have been written on the Battle of Antietam and the Maryland Campaign, none have narrowed down a particular phase as this book does.” —Ted Alexander, Chief Historian at Antietam National Battlefield Park and a Smithsonian Associates tour guide specializing in Civil War sites “Marion Armstrong has a done a good job examining the generalship at Antietam. This is a terrific book.” —John Michael Priest, noted author of books on Antietam and teacher at South Hagerstown High School in Boonsboro, Maryland Marion V. Armstrong Jr. is a retired U.S. Army reserve officer and teaches history at colleges in middle Tennessee.