Gouverneur K. Warren, a brilliant student at West Point and a topographical engineer, earned early acclaim for his explorations of the Nebraska Territory and the Black Hills in the 1850s. With the start of the Civil War, Warren moved from teacher at West Point to lieutenant colonel of a New York regiment and was soon a rising star in the Army of the Potomac. His fast action at Little Round Top, bringing Federal troops to an undefended position before the Confederates could seize it, helped to save the day at Gettysburg. For his service at Bristoe Station and Mine Run, he was awarded command of the Fifth Corps for the 1864 Virginia campaign. Warren's peculiarities of temperament and personality put a cloud over his service at the battles of the Wilderness and Spotsylvania and cost him the confidence of his superiors, Grant and Meade. He was summarily relieved of his command by Philip Sheridan after winning the Battle of Five Forks, just eight days before Appomattox. Warren continued as an engineer of distinction in the Army after the war, but he was determined to clear his name before a board of inquiry, which conducted an exhaustive investigation into the battle, Warren's conduct, and Sheridan's arbitrary action. However, the findings of the court vindicating Warren were not made public until shortly after his death. For this biography of Gouverneur Warren, David M. Jordan utilizes Warren's own voluminous collection of letters, papers, orders, and other items saved by his family, as well as the letters and writings of such contemporaries as his aide and brother-in-law Washington Roebling, Andrew Humphreys, Winfield Ha ncock, George Gordon Meade, and Ulysses S. Grant. Jordan presents a vivid account of the life and times of a complex military figure.