Horace Porter served as lieutenant colonel on Ulysses S. Grant's staff from April 1864 to the end of the Civil War. He accompanied Grant into battle in the Wilderness, Cold Harbor, and Petersburg campaigns, and was present at Lee's surrender at McLean's house. Throughout the war, he kept extensive notes that capture Grant's conversations, as well as his own observations of military life. Porter's portrait of Grant is the most comprehensive first-hand account that we have. We see Grant as a soldier and hear in his own words the tactical evaluations that led to many of the war's key decisions. We also hear of Grant's dealings with Lincoln, of the close relationship between Sherman and Grant, and of Lee's noble bearing at his surrender. This is a stirring account of our country's most memorable conflict.
The one real weakness of the memoirs in terms of historical accuracy, as pointed out in the Introduction, is the extensive quoting of Grant and others. Porter kept extensive and careful notes, but it seems questionable that he did so, for example, on horseback. Yet several times, he quotes Grant and conversations with Grant that took place on horseback or in the field under conditions that were too active to allow Porter to stop and record conversations! But even if not precisely accurate, they do give the flavor of the way Grant thought and talked. The same is true of those conversation and quotes attributed to Lincoln, although in this case it may be assumed that Porter would have had ample time to record the conversations either as they occured or right afterward.
Porter's descriptions of Lincoln are touching; his memoirs describe Lincoln as other saw him at the time as well--a man burdened by responsibility and sadness, but with a shrewd judgement of people and situations. Clearly, Porter revered Lincoln and portrays Grant and other officers as having tremendous esteem and personal affection for the President. So did the soldiers of the Army of the Potomac; Porter describes (as did others) the enthusiasm with which the rank and file greeted Lincoln on every occasion.
Porter minimized Grant's reverses and defeats; reading his account of the Battle of the Wilderness, you would think it was a Union victory. His defence of Grant's disastrous assault at Cold Harbor is nothing short of patheticly feeble, that of someone grasping at straws to save the reputation of an idolized commander who made a disastrous mistake.
Shortcomings aside, these memoirs are valuable and interesting for the portrayal of Grant as a human being, as well as a detailed and fascinating account of the day-to-day life of Grant and his staff in the field.