Excitement about things became a habit, a part of my personality, and the expectation that I should enjoy new experiences often engendered the enjoyment itself.

When you are an historian, there's probably nothing that matters more than to be recognized by your colleagues in your own profession. I was lucky enough to win the Pulitzer Prize for History. I had to give a talk right after that to some young people. The most important thing to tell them, I think, is that you can't ever know that it's going to turn out that way.

Politicians generally form alliances and not friendships. Individuals and institutions achieve their ends through continual barter. But deals are not bonds. Indeed, intense emotional involvement with anything - with issues, ideology, a woman, even a family - can be a handicap, not only consuming valuable time, but more importantly, reducing flexibility and the capacity for detached calculation needed to take maximum advantage of continually changing circumstances.

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.

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.

I liked the thought that the book I was now holding had been held by dozens of others.