Though [Abraham Lincoln] never would travel to Europe, he went with Shakespeare's kings to Merry England; he went with Lord Byron poetry to Spain and Portugal. Literature allowed him to transcend his surroundings.

I think the most important thing I wanted to say at various times to Franklin and Eleanor Roosevelt was that it seemed so sad to me that - I really believe they loved each other and had a great deal of affection - but because of that early hurt in their marriage, there was a certain kind of distance from then on, until their deaths actually. So at times, I just wanted to push them together and say, "Come on, you guys! I know you love each other. This is crazy!"

When I do research, I have done - 90 percent of my time is the research, the other ten percent is the writing. So I don't have to face a blank piece of paper. I can look at this as a quote that I have from somewhere.

One of the important qualities that I think is often overlooked is just energy. It's vitality, and sort of a life force that some people have and others don't. Probably that is connected to a love of whatever it is that they're doing. Another quality that I think is central is confidence. Again, some people are more blessed with that than others.

If you interview five people about the same incident, and you see five different points of view, it makes you know what makes history so complicated. Something doesn't just occur. It's not like a scientific event. It's a human event. So the dimensions of it will be seen differently by different people.

Washington was a typical American. Napoleon was a typical Frenchman, but Lincoln was a humanitarian as broad as the world. He was bigger than his country - bigger than all the Presidents together.

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.