Yes, that's fine. His last few books, about his life before the wilderness, are great reads. This guy has had TWO amazing lives! Maybe that's the secret to still being so wide-awake at his age? Or is it because he never married?
By the way, if you can track down his old biographies on people, like the John Wayne for instance, they are great. I think it's just called Duke, full of stuff I'd never read about him.