Jodi Picoult, chronicler extraordinaire of hot-button issues, has just published her 18th novel, "House Rules," in which a teenager with Asperger's syndrome (a form of autism) is accused of murder. She talked recently from her New Hampshire home about what makes her curious, the role of motherhood in her writing and the movie version of her most popular book.

Q Your books often follow a template, with an emphasis on families, relationships, a medical issue or other crisis, sometimes a court case. It's a formula that works for you; how did you first develop it?

A I would actually warn against calling it a formula, honestly, because the books are about such wildly different things; not all of them have court cases, not all of them are about families.

A lot of them are, but not all of them. When I do write about the law, it's because I've found something about the legal system that seems so bizarre, I feel the need to tell other people about it. In this particular case, in "House Rules," you're dealing with a kid who can't communicate the way the legal system wants us to, and everything kind of falls apart then.

Q Can you use this book as an example of how you start thinking about your stories?

A Usually it's a what-if question that I can't answer, and if I keep wondering about it, it's probably a really good idea for a book. And the what-if question here developed in talking to an attorney about what if you couldn't communicate a certain way in court. At the same time, I was thinking about a relative of mine, a cousin who is autistic -- not with Asperger's, like Jacob [her protagonist], but profoundly autistic. His mom was routinely called on the carpet by store owners, and in some cases the police, when she had to control his meltdowns in public. There's that hard schism that breaks down between law enforcement and autism that I thought was really interesting to explore.

Q You're well known for your exhaustive research; how much time do you spend on that part of the process?

A Well, it totally depends on the book. This one was probably about three or four months of research; in addition to the legal stuff and shadowing a crime scene investigator, I also talked to a lot of kids who have Asperger's. I met with six of them face to face, had long interviews with them. I wanted to see how they presented themselves; I wanted to know how the other characters felt coming in contact with Jacob. I also knew that they could not answer the questions as well as they could if they were written. So I had 40 more kids with Asperger's complete very long questionnaires, and they wrote me back dozens of pages, with answers that were in unbelievable depth and detail and showed incredible mental prowess. A lot of their experiences and their commentary wound up in Jacob's voice.

Q You often use alternating narrators. Is this more of a challenge in telling the story? And which voice is the easiest for you -- the mother's, perhaps?

A Actually, that's the hardest. Because I have to try really hard not to be the mom and not to have her sound like me. So it's always really challenging, whenever I write a mom.

I'll tell you that for me the easiest voices were Jacob and Theo [his younger brother]. I loved writing Jacob; he's one of my favorite characters I've ever written. I think meeting with all those kids really helped me see where they were coming from and be able to channel them a little bit.

Q How do your own views of motherhood and family affect your stories?

A I think it really affects what I write. Because if you kind of look at the linear arc of what I've chosen to write about, I started out [in "Songs of the Humpback Whale"] by writing about the relationship between a mother and a daughter, but I was closer in age to the daughter. And then I moved into the relationships between men and women, and marriages, and whether they're ever equal. After I had kids, I began to look at all the scary things that could happen. And that really has become the trajectory of many of my books, whether it's kidnapping, or school violence, or some kind of disability, or an illness -- any of those things that are some of my greatest fears as the mom.

Q You are awfully prolific, writing about a book a year. Is this because your fans expect that, or do you just feel compelled to put these stories out?

A A little of both. If a book were going to take longer than a year, then everyone would just have to wait for it. But on the other hand, I do think that it's important to stay connected with your readers. It's a pretty fickle world out there. So it's really nice for me to be able to come out every year and say, "Hey, here's another one, don't forget about me."

Q Do you have an idea in mind for your next book?

A I just finished the first draft; you can read excerpts on my website. It's about gay rights and embryo donation.

Q I have to ask how you felt about the movie version of "My Sister's Keeper."

A I actually was not very pleased with the way they edited it -- mostly because although no author has complete control over the movie version, unless you're J.K. Rowling, I had made it very clear that changing the ending changed the message of the story. And although the director [Nick Cassavetes] promised me that he would not change the ending without telling me and explaining why, he never did. I found out from a fan who read the script at a casting agency, and when I confronted the director, he basically tossed me off the set. So unfortunately, I think my story kind of got compromised. He made a beautiful movie, but it's not the story that I wanted to tell. It's the story that he wanted to tell.

Q So, would you let anyone make a movie of any of your other books after that experience?

A I would, because I think that the reason you sell the rights to film is not because you expect to see your book represented in total accuracy, but because there are so many more people in today's world who watch TV or watch movies than read. Very often you can find a whole new group of readers by translating your book to the screen. And I have had hundreds of e-mails from people who said, "I never heard of you before, but I read the book 'My Sister's Keeper' after I saw the movie, and now I've read everything that you ever wrote!"

Cynthia Dickison is a features designer at the Star Tribune.