Lincoln appointed Grant as General in Chief of the Armies of the United States on March 10, 1864. Grant believed that up to that point, Union armies in different theaters had "acted independently and without concert, like a balky team, no two ever pulling together." Accordingly, his strategic plan for 1864 called for putting five Union armies into motion simultaneously against the Confederacy. While three smaller armies in peripheral theaters tied down significant Confederate forces the two main armies, Meade's Army of the Potomac and William Tecumseh Sherman's army group at Chattanooga would lock horns respectively with Lee in Virginia and Joe Johnson's Army of Tennessee on the road to Atlanta. The simultaneous advance of several armies is called "concentration in time." As General in Chief, Grant chose to accompany Meade as he took on Lee. For nearly forty days, the Army of the Potomac and the Army of Northern Virginia were in nearly constant contact--at the Wilderness, Spotsylvania...