Gettysburg, late afternoon, Thursday, July 2, 1863.The Union left wing is a shambles. General Dan Sickles has been carried from the field with a gruesome wound and his Third Corps is in full retreat.Confederate troops cross the Emmitsburg Road and advance on the center of the Union position. There is no coherent Union line, just two-thirds of an over-extended Second Corps scattered the length of Cemetery Ridge. A desperate Winfield Scott Hancock organizes a defense, placing artillery batteries, hurling regiments forward, trading men for time. It is a masterful performance under extreme conditions.The Union and Confederate forces collide in Plum Run Ravine. More than at any other point in the three days of fighting, the issue hangs in the balance. This great battle is reduced to less than an acre of ground.This book pays close attention to the terrain, how it shaped the battle, how it dictated the movement of troops and how it guided Hancock's decisions. The thrilling narrative and the detailed driving and walking tour make it a must for both casual and serious students of the battle.