What I think I've learned is that you're never going to get it all right, and you can't obsess about having a fact wrong or a date wrong or something like that, as long as you tried as best you could. If you've done the kind of research that you're sure is pretty good, then you just have to have confidence in it, so that nothing is perfect in life. I think that is what the criticism has helped me to understand.

That is what leadership is all about: staking your ground ahead of where opinion is and convincing people, not simply following the popular opinion of the moment.

My books are written with a strong chronological spine.

What interested me most about the Kennedys was the family situation. Somehow, they had created this family that lasted over time, they had a sense of connection to one another. Especially now, when people are spread all over the country and they don't see grandparents and parents, this family bonded together.

An adult friend of Lincoln's: "Life was to him a school.

There are 20,000 million books I could have to read, but I can pick the ones and know that I'm learning something that I didn't know before. That's the glory of writing. It's not even so much the writing, it's what you learn - especially history - because so much of it is research.

If your ambition comes at the price of an unbalanced life, that there's nothing else that gives you comfort but success, it's not worth it.