If you only read one book on the subject, and I hope it will be many more, I'd recommend Gen. Porter Alexander's Fighting for the Confederacy. Lee's artillery commander, Alexander was at most all the major battles in the eastern theater, and he wrote the book for his family with no intention of publishing it. His heirs published it and many of us are so glad they did!
A finely written account with the 'I was there' viewpoint and authority.