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.

Let's say that history is what happened. The record of what happened is how each individual happens to see those events. They've already been filtered. When the historian or biographer takes over, history is no longer exactly what happened, because there has been a process of selection going on; it's impossible to write about anyone, any event, in any period of time, without in some way imposing, even unconsciously, your own standards, your own values.

Thomas Jefferson once said, "Women shouldn't wrinkle their pretty little foreheads with politics." Now does that mean he was a sexist, or was he just expressing what most males, and maybe most females, felt at that time? Or are both true?

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.

I think that today's books, in which every quote, every conversation, is taken from a memoir, an autobiography, an interview, or what-have-you, are much more convincing.

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.

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.