It's the story of a boy who doesn't know his name, written by a man whose name comes from his twin sister who couldn't pronounce his real name. "Crispin: The Cross of Lead" by Avi won the Newbery Medal in January, making it the "best children's book" of the year.

"Crispin" takes place in 14th-century England and is part mystery, part thriller, part history. In "Crispin," Avi's lead character is a peasant boy who has lost his mother. In the 50 books he has written, Avi's lead characters have included a mouse named Poppy, a 13-year-old girl sent alone to America in 1835 and a magician who lives in the 1400s. How did Avi, 66, decide he wanted to write children's books and where does he get his ideas? He spoke recently with Tracy Grant from his home in Colorado.

You write mysteries, historical books, fantasy. How does one person come up with such different ideas for books?

Getting ideas is an aspect of being interested in many things. I'm interested in . . . the world, the history of the world, people and so forth. There are so many fascinating aspects to the world. . . . What if I were a specialist in trees, I would know the name of every tree, I would understand things that everyone else who just sees the trees would not notice. For me, my world is the world of stories, and so I see stories everywhere.

What is the first thing you remember writing?

It wasn't writing, it was reading. At the age of 5, I burst into the family room saying, "I can read. I can read." I have no memory of it, but it's a family story. The earliest piece of writing that seems to have survived is a play about cops and robbers that I probably wrote when I was in fourth grade.

How long does it take you to write a book?

The longest it ever took me to write a book was 14 years ("Bright Shadow"). The shortest is one day ("Sore Losers").

On the whole, it takes about a year and a half. I rewrite endlessly. Writing is rewriting. My definition of writing is rewriting so that strangers can understand what you're thinking and feeling.

How did you decide to write children's books?

I made up my mind to become a writer when I was in high school. My original intent was to write plays for the theater . . . but I wasn't very good at it. The truth is that I had kids and it was the kids who brought me to children's literature. [He has five children: two adults, a college student, a high school senior and an eighth-grader.]

You had trouble writing as a child. How did you overcome that?

I have dysgraphia and it's a little bit like dyslexia but nowhere near as severe. There's some quirk in the brain that causes odd word substitutions, letter substitutions. So it looks like my work is very sloppy. My problem is not with the ideas but with getting the ideas written down.

[Dyslexia makes reading hard. A word like "blue" might look like "lbue." With dysgraphia, when writing the word "blue" it might come out "bloom."]

It's something I've learned to live with, but when I was a young person it drove me crazy and it drove my teachers crazy. I was discouraged from becoming a writer. One of the great moments in my life was when I learned to use a computer with a spell-checker. People ask me how I felt when I won the Newbery: It didn't compare to how I felt when I first used a spell-checker. That was release from bondage.

"Crispin: The Cross of Lead," about a peasant boy who lost his mother, won the Newbery Medal in January.Avi's 50 books include "Crispin" and "Silent Movie."