William Passmore Carlin (1829-1903), a native of Illinois, graduated from West Point in 1850 and served on frontier duty and in Utah before the Civil War. He began his Civil War career as the colonel of an Illinois regiment, served with distinction in early fighting in Missouri and Mississippi, and participated in important command roles at the battles of Perryville, Stones River, Liberty Gap, Chickamauga, Missionary Ridge, Buzzard Roost, Resaca, Kennesaw Mountain, Jonesboro, and Bentonville and at the siege of Atlanta. He was a successful and important brigade and division commander from Perryville to Sherman's March to the Sea and into the Carolinas at the close of the war. Carlin remained in the army until he retired in 1893 as a brigadier general after significant further service in the West. To supplement Carlin's memoirs, the editors have provided two biographical essays and extensive annotation. They have consulted manuscript holdings in twenty-five repositories, including pertinent material from diaries, letters, reminiscences, and unit histories written by contemporaries. Readers of these memoirs have a rare chance to follow the career of an officer from the 1850s through Reconstruction and beyond.