I read Grant’s memoirs recently. If you have a Kindle, you can download it for free at Amazon.
He had a lot of respect for Lee, but at the same time, he was emphatic in his view that Lee was misrepresented by the press as a much greater general than he was. Having fought with Lee in Mexico, he knew that Lee was not invincible. The media in both the South and the North, however, portrayed him as such.
As far as his military philosophy was concerned, his was not all that different from Lee’s. He believed that he who attacks offensively carries the day, particularly after he’s demonstrated a time or two that he can do so and prevail. At that point, the opponent becomes demoralized, and is easily made to retreat.
As I stated, Lee had the same philosophy, but at Gettysburg, he took it way too far. He apparently began to believe that he WAS invincible. There is really no other way to describe the battle plan he concocted. It was pure recklessness.
Lee’s real problem at Gettysburg was the loss of Jackson who was his #1 offensive field commander. Longstreet was much better on defense. That and Stuart suffering from an attack of the stupids and depriving Lee of intelligence by riding off in search of glory.