The Overland Campaign was like no other Civil War campaign, and shares more similarities with the First World War than with earlier battles such as First Bull Run and Shiloh, and was made more horrific by the meeting of passion and technology in the first of our "modern" wars. Gone was the old practice of marching out of camp to fight a battle and then, win or lose, marching back to camp to refit before fighting another. This campaign was a relentless struggle, a dance of death through tidewater Virginia, with the Union Army under U S Grant continually trying to outflank Lee's Army of Northern Virginia. Every flanking maneuver found Lee's ragged veterans blocking the way. Grant was every bit as aggressive as Lee, and he had the manpower of the North to back him up. They started calling him "Butcher" Grant, and someone told him that his and Lee's armies would be like the Kilkenny cats that devoured each other. Grant grimly said, "Our cat has the longer tail." It was part of a two-pronged plan. Years later, Sherman summed it up by saying, "Grant was to go for Lee and I was to go for Joe Johnston".
Source: The Publisher Website.