Lauren Oliver: 'I don't believe in happy endings'

She is the biggest thing in Young Adult fiction right now. So why does she feel so conflicted, asks James Kidd

White house fan: Barack Obama bought Lauren Oliver’s books for his daughters (Micha Theiner)

It is tempting to view Lauren Oliver's literary career as working in reverse. Arguably the hottest property in Young Adult fiction right now, Oliver spent her own teenage years reading Henry James and nursing a precocious ambition to compose the great American novel. "I was failing to write these long, depressing books," says the 29-year-old. "My first novel was about a 35-year-old whose wife dies of cancer and who takes up with a prostitute. It was ridiculous." These fledgling efforts earned Oliver an agent but little else. "They were roundly rejected by every publisher because they had no plot. I was writing boring books."

Oliver sublimated her ambition to be a novelist by working for Penguin in New York. It was on this supposedly grown-up stage that she began reading stories for young adults. "These novels were strange, ambitious and entertaining. They had stories that propelled you. I feel a lot of adult fiction looks down on plot as a lesser form of literature."

Oliver's first novel for teens was Before I Fall, a smart, vibrant and romantic re-imagining of Groundhog Day. It was followed by the trilogy of Delirium, Pandemonium and now Requiem. Currently being filmed for US television, the series is attracting the highest-profile fans. Barack Obama was photographed in a Virginia bookstore buying Delirium and Pandemonium as Christmas presents for his daughters.

Set in a dystopian America where romantic love is illegal, Requiem completes a story that is epic and intimate at the same time. Oliver's two narrators, Lena and Hana, face stark choices between freedom and security, rebellion and conformity, certainty and mystery, and, of course, boys who are brooding or boys who are more genial. Oliver plays skilfully with genre conventions, and tackles grand narratives with an intelligence that should make some adult novelists blush.

Nevertheless, not everyone is thrilled. "Requiem has been controversial because people don't feel I gave it closure," says Oliver. But the deliberately incomplete finale encapsulates the entire point of the trilogy. "It's a coming-of-age story. Part of what adults have to live with is ambiguity. It's not like you make a choice and find happiness hiding behind one of three doors looking like Kim Kardashian. You have to choose what you want every day. There is no one point at which you get your happy ending."

Oliver's conversation, like her books, also puts many so-called "serious" novelists to shame. Despite jet lag and a half-serious claim to "misanthropy", her ideas bounce around like hyperactive puppies. Whether she is unpicking her "politically bifurcated country" or talking about her personal life, she answers questions with eloquence and openness.

She mentions Lena's uneasy reunion with her mother, who abandons her children in her desperation to escape political and social oppression. "That theme of betrayal reflected the fact that a person I dated for four years and was engaged to died at 29 due to substance abuse issues. I only realised it in retrospect, but I think Lena's agonising about her mother reflected my own feelings – why wasn't I good enough to stay alive for?"

One could see Oliver as encapsulating the extremes of her two heroines. "There are times I wish I was more conventional," she says. "I would get a husband and a baby and a big SUV in the 'burbs and be happy. But forging my own way – my career, my relationships with wonderful but troubled people – that's who I am."

Raised in Westchester, Connecticut, she describes her upbringing as liberal and comfortable. Her mother and father are literature professors who divorced when Oliver was young, then re-married to other literature professors. "My parents were pretty liberal, but they were still parents. I definitely had my teenage rebellion." What sort of things? "Nothing I would repeat on record," Oliver laughs. "I was kind of a wild teenager, but I always got great grades at high school. I became a huge nerd later in life."

Oliver takes her success seriously but wears it lightly. Clearly ambitious, she divides her time between writing and a publishing venture, Paper Lantern, that encourages teenagers to write fiction. "I didn't miss working in a traditional publishing house – certainly not the dress code or meetings – but I did miss working with writers. We're a small operation – the five of us meet around my dining room table. We are experimenting with an e-venture and looking for new writers."

Oliver herself has two new books ready for publication next year. A Young Adult novel called Panic ("about a dangerous game played by adolescents"), and The Rose which is aimed at more "mature" readers. ("A family clear out a house after the death of a patriarch.") Whether this signals that Oliver has come full circle or is simply growing up remains to be seen. What she does know is that today's teenagers can heal the social and political rifts in her divided nation.

"The good news is that teenagers agree on the most divisive issues in America: 75 per cent of young people support gay marriage. There is definitely the sense that future generations can heal the rift in the US." She says much the same about their attitude to literature. "I have never met a teenager – and I probably meet 5,000 a year – who prefers ebooks to real books. Their parents like ebooks. Teens like to own a book and have it on their shelves."

Before she disappears for a well-earned afternoon nap, I ask about her most famous young readers, Malia Ann and Sasha Obama. Having campaigned for Obama in 2008, Oliver could not imagine a better endorsement. "All I can say is that they have excellent taste. It is just so flattering. A friend said: 'When a celebrity reads your book, that's great. But the President – he is really famous.'"

Requiem by Lauren Oliver

Hodder & Stoughton, £12.99

"... Welcome to the free world. We give people the power to choose. They can even choose the wrong thing. Beautiful, isn't it?"