You took three years after high school to travel around the world. How much of that experience has flowed into your YA novels? 

It’s not so much that the travel seeped into my novels—though in the case of Just One Day/Year, it did, rather directly—but the travel informed the person that I am. Travel changed me. It made me a more empathetic person. more aware of the vast commonalities among different peoples, and also how different cultural lenses change perspective. Which impacts me as a human being, as well as a novelist. My favorite thing about travel is how it pushes you out of your comfort and as a result, you expand your comfort zone. I think the characters in my novels all follow similar journeys, whether they go on literal journeys or not.

You started your career writing for Seventeen magazine and later in your life you based your first YA novel on one of the story you wrote for that magazine. How has your experience in Seventeen influenced you as YA writer?

It was no accident that I worked at Seventeen. I sought out to write for a magazine for teenagers. At the time, those magazines were running what I thought were most interesting and well-written (or vibrantly written) articles and I wanted to a part of that. loved working at Seventeen, writing about young people and for young people. When I sat down to write my first YA novel, Sisters in Sanity, which was based on an article I’d written at Seventeen nearly ten years before, it was both a surprise—I didn’t know that I wanted to write novels, for teens—and a homecoming because of course I had been writing about and for young people all along.

Mia and Adam's story has just jumped from the paper to the big screen. How was your involvement in the project? How do you feel about the result?

I was an executive producer on the If I Stay film, which means that I got to be involved in all phases of the project, from the script development to being on set during filming to seeing early cuts of the film. I loved watching how the (brilliant) filmmakers took the story from page to screen. They put so much deep thought and consideration into it. And it’s kind of amazing how something that works on the page doesn’t work on the screen. It has to be changed in order for it to stay the same. I was thrilled with the result. I felt like the characters in the film felt very much like the characters that had lived inside me all those years and what I really loved about the movie was the music. There is only so much you can do on the page with music. The movie brought it to life.

Where She Went might become a movie. Where do you think would be the greatest challenges to get Where She Went into the big screen just as the readers would like?

I think of all my books, Where She Went is probably the fans' favorite, so I think the biggest challenge is taking something that fans hold close to their heart and making the necessary changes to bring it to the screen. A lot of that book is Adam and Mia walking and talking and while I love the Before Sunrise/Sunset movies, which are mostly walking and talking, I think a Where She Went movie would have to be a little bit reimagined. If it were done well, fans would go along for the ride, i think.

Why did you decide to write Allyson and Willem's story using both points of view each in a book? How does one book complement the other?

With If I Stay/Where She Went, I had no intention of writing a sequel, but after I finished If I Stay, Adam and Mia kept waking me in the night, demanding I finish the story and as soon as I started thinking about their future, I knew the story would be Adam’s.With Just One Day/Year, the idea of telling the interlocking stories was part of the challenge and the appeal of writing the books. 

I wanted readers to finish one book and have one idea of how things had gone down and finish the other and have a different idea. Going back to the question about what I learned from all my travels: perspective changes everything.Which was why I wanted to the books to work like that.

I think after you read the second book, Willem’s story, you really see how the two books work together, because the reader has this unique vantage point: knowing things about Allyson and Willem that they don’t know about each other. To me, that’s a very satisfying read.

We know the inspiration stories behind your other books. Where did the inspiration for I Was Here come from?

Inspiration comes from a lot of sources. On one hand, I Was Here was based on an article I’d done for Cosmopolitan about young women and suicide. There was young woman named Suzy Gonzales who really stuck with me. Like Meg in I Was Here she was brilliant and charismatic and no one knew she was suffering when she killed herself. Also like Meg, she’d been involved with a suicide support group, the kind that supports your decision to end your life. So that was one aspect of it. But I was also interested in writing about friendship, about the deep heartbreak of losing your best friend, and about what it’s like to give away your power to someone else, as Cody had, and to take it back, as Cody does.

In I Was Here you deal again with the death of loved ones. What are the differences between the approaches in this new novel and in If I Stay (and Where She Went)?

In certain ways they are the same, a character dealing with the aftermath of deep loss. I Was Here is probably a darker book because there is something about suicide that just leaves a certain kind of scar. And whereas If I Stay and Where She Went both have a similar structure—they take place in one day and alternate between present tense and flashbacks—I Was Here utilizes a different structure and is more of a mystery really because Cody is trying to piece together the cause of Meg’s death.

And now, what book project comes next?

I just finished my first book about adults—I hesitate to say for adults because I don’t see why books about young people are just for young people and books about adults are just for adults. It’s about a mother and a wife and it was kind of wonderful exploring this other aspect of my life. It comes in the US next year.