The Battle of Antietam has been called the bloodiest single day in American History. By the end of the evening, 17 September 1862, an estimated 4,000 American soldiers had been killed and over 18,000 wounded in and around the small farming community of Sharpsburg, Maryland. Emory Upton, then a captain with the Union artillery battery, later wrote, “I have heard of ‘the dead lying in heaps,’ but never saw it till this battle. Whole ranks fell together.” The battle had been a day of confusion, tactical blunders, individual heroics, and the effects of just plain luck. It brought to an end a Confederate campaign to “liberate” the border state of Maryland and possibly to take the war into Pennsylvania. A little more than one hundred and forty years later, the Antietam battlefield is one of the best-preserved Civil War battlefields in the National Park System.

When Joseph Hooker had relieved Ambrose Burnside after the disastrous Fredericksburg campaign, he found the Army of the Potomac in a low state of morale. Desertion was increasing, and the army's own interior administration - never good - had deteriorated.

The battle of Chickamauga, fought on 19-20 September 1863, was the bloodiest battle in the western theater during the American Civil War. Along the banks of Chickamauga Creek in Northwest Georgia, less than a day's march south of Chattanooga, Tennessee, the Union Army of the Cumberland led by Maj. Gen. William S. Rosecrans clashed with Confederate General Braxton Bragg's Army of Tennessee in a two day mêlée that left almost 35,000 men dead, wounded, or missing.

At the start of the Fredericksburg Campaign, the Union Army of the Potomac managed to steal a march on the Confederate Army of Northern Virginia. But owing to the failure of the Federals' pontoon bridge equipment to arrive at the crossing of the Rappahannock River as scheduled, the Southerners were able to block the road to Richmond. The Union commander, General Burnside, decided to launch a frontal assault against the Confederate position at Fredericksburg, resulting in one of the Union Army's most lopsided tactical defeats of the Civil War.

Ad helium Pace Parati: prepared in peace for war. This sentiment was much on the mind of Captain Arthur L. Wagner as he contemplated the quality of military education at the Infantry and Cavalry School at Fort Leavenworth, Kansas, during the 1890s. Wagner believed that the school's curricula during the long years of peace had become too far removed from the reality of war, and he cast about for ways to make the study of conflict more real to officers who had no experience in combat. Eventually, he arrived at a concept called the "Staff Ride," which consisted of detailed classroom study of an actual campaign followed by a visit to the sites associated with that campaign. Although Wagner never lived to see the Staff Ride added to the Leavenworth curricula, an associate of his, Major Eben Swift, implemented the Staff Ride at the General Service and Staff School in 1906. In July of that year, Swift led a contingent of twelve students to Chattanooga, Tennessee, to begin a two-week study of the Atlanta campaign of 1864.