Much has been written of the infantry and the cavalry during the Civil War, but little attention has been paid the artillery. Through the battles of Chickamauga and Missionary Ridge in 1863 and the Atlanta Campaign of 1864 and with General Sherman' s forces on the famous March to the Sea, the acts of a courageous fighting group are vividly recounted in Behind the Guns: The History of Battery I, 2nd Regiment, Illinois Light Artillery. Originally published in 1965 in a limited edition, this regimental history of a light artillery unit was written by three of its soldiers, including the bugler.              Battery I was formed in 1861 by Charles W. Keith of Joliet and Henry B. Plant of Peoria. More than a hundred men were mustered into service in December near Springfield and left for Cairo in February 1862. The battery trained at Camp Paine across the Ohio River in Kentucky until March, when the men were dispatched to the South. During the war, the Battery was attached to three different armies: the Army of the Mississippi, the Army of the Ohio, and the Army of the Cumberland.              Clyde C. Walton' s foreword and the narrative discuss the variety of weapons used by the unit, including James, Parrott, and Rodman guns and the bronze, muzzle-loading Napoleons that fired twelve-pound projectiles. The book also includes an account of the prisoner-of-war experience of Battery I lieutenant Charles McDonald, biographical sketches of the battery soldiers, and eighteen maps and five line drawings.