Although I disagree with most of what has been posted by "UncCump", I would concede that, the greatness of Grant was being the tenacious General that the Federals needed, in order to defeat such a formidable foe as the ANV. Only the continuous sacrifice of Union troops could wear down Lee's force. Grant's tactics, strategy, or military knowledge did not make him a "Great General". However, his most redeeming character (IMHO) was the benevolence he demonstrated at Appomattox. What other General would have had the foresight, the political might, and the will, to offer such an honorable surrender? That was the "Greatness" of Grant.