I try to find clues in the documented record - from the subject's own testimony, from the testimony of other people. When you're writing a biography, you're trying to understand your subject in the same way that you try to understand one of your friends, and that effort at understanding is always very imperfect.

Writing history and biography for kids calls for special skills that can only be acquired through practice and that are different from those required for an adult audience.

With the audience I write for, I want to make sure that the reader is eagerly turning every page. I want each of my books to be an absorbing reading experience, an authentic piece of literature. The worst thing that can happen is for a book to have a chilling effect on the reader, to have a kid pick it up and look at a bunch of footnotes and think, No, I'm not going to read this, it's too intimidating.

Anyone writing a picture-book biography of Lincoln has a different set of responsibilities from someone writing a biography for sixth-graders, say, or from a Lincoln scholar writing an academic book on Lincoln. Each of these writers has a different audience and different goals. That's obvious.

Digging up new information and speculating on it isn't your primary purpose when you're writing a biography intended for young readers, unless you find compelling evidence that departs from the accepted wisdom. A biography for young people calls for the demanding art of distillation, the art of storytelling, and your responsibility is to stick as closely as possible to the documented record.

I get letters from two kinds of readers. History buffs, who love to read history and biography for fun, and then kids who want to be writers but who rarely come out and say so in their letters. You can tell by the questions they ask - How did you get your first book published? How long do you spend on a book? So I guess those are the readers that I'm writing for - kids who enjoy that kind of book, because they're interested in history, in other people's lives, in what has happened in the world. I believe that they're the ones who are going to be the movers and shakers.

The Declaration of Independence, the Constitution, and the Bill of Rights were all written by affluent white males, but to discuss them in any meaningful way, you have to bring in the roles of African Americans - the enslaved blacks - and the roles of women, who were scarcely acknowledged by those documents. You have to discuss why slavery wasn't outlawed by the Constitution, why women weren't given the votes. The Bill of Rights isn't about dead white males anymore, and it's not just about live white males either; it's about every minority group that exists.