Jodi Picoult enjoys tackling hot topics in her novels.

Jodi Picoult enjoys tackling hot topics in her novels.

It seemed like such a good idea at the time. "Will you chair Jodi Picoult's Auckland event," they asked me. "Yes, yes," I replied blithely. No problem.

Cut to Picoult and I standing in the wings of the stage at the Dorothy Winstone Centre peering through the curtains at hundreds of expectant faces. I'm not sure why it hadn't occurred to me that there would be quite so many people there. Picoult is queen of the best-sellers, after all. Her latest novel, Change of Heart (Allen & Unwin, $37.99) had an initial print run of one million copies and shot straight to number one on the New York Times bestseller list. She's sold 200,000 books in this country alone which, given the size of our market, is huge.

Picoult is a lot less fazed by the crowd than me. She's in the final days of a three-month publicity tour, is suffering from tendonitis because she's signed so many books and is "desperate to be in my own bed with my own husband beside me" - yet still she seems excited to be there, meeting her fans.

Normally at Readers & Writers Festival events I feel positively youthful compared to the rest of the audience. But here, as well as the grandmas, there are rows and rows of teenage girls.

At question time they're asking Picoult about stuff she's posted on her website or telling her how they and their school friends discuss the issues raised in her novels.

Picoult is famous for writing about hot topics: high-school shootings, stem-cell research and, in this her 15th novel, the triple whammy of religion, the death penalty and organ transplants. But, like all her tales, at the heart of the story is the complicated relationship between a parent and a child.

Change of Heart is the story of carpenter Shay Bourne who's on death row for the murder of June Nealon's daughter and her husband. Shay has decided he wants to donate his heart to June's desperately sick daughter. Only trouble is, he's scheduled to die by lethal injection which will stop his heart and make it useless.

The story is told through the voices of Maggie the lawyer who signs on to help Shay in his fight for death by hanging, Michael the priest who finds himself questioning his faith, Lucius the HIV-positive prisoner in the next cell, as well as June the mother who knows that only the heart of the man she hates can save the life of the child she loves.

When it comes to research, Picoult enjoys putting in the hard yards. For previous novels she's lived with an Amish family and observed cardiac surgery. For this one, she spent time on death row in an Arizona prison and is still pen pals with one of the condemned men.

"He keeps me up to date with TV shows I've missed and sends me amazing artworks he's made using the pigments out of M&Ms and Skittles because he doesn't have access to paints," she says. "He's a lovely man. The only thing is that during an armed robbery 10 years ago he injected a man with battery acid and killed him."