She is one of the world’s most successful authors, selling over 80m books – but her latest will be her last. She talks to a lifelong fan about love, luck and why thinking like a child saved her life

My parents raised me, of course, but it was a different adult who shaped my mental landscape. My imagination, my capacity for empathy, my sense of curiosity and my awareness that, while I was unique, I wasn’t alone: others felt the same fears and feelings as me. On top of all that, this woman taught me about menstruation, masturbation, making out and sex, which is a damned sight more than any teacher ever did. I was not the only one she took under her wing: there are millions and millions of us who were shaped by her – whole generations who grew up under her tutelage – because this woman is Judy Blume.

Blume’s achievements can be described in facts and figures: book sales of more than 82m over a 45-year career, awards from everyone from the Library of Congress to the National Book Foundation. Are You There, God? It’s Me, Margaret, Blubber, Deenie, Tiger Eyes, Forever – to list her books is to list some of the most popular books ever written for young people. But while these details convey Blume’s commercial impact, they don’t give a sense of her emotional power. To do that, you need to look to the individual children who read her books and the effect she has on them.

I began reading Blume’s books when I was seven, starting with Tales Of A Fourth Grade Nothing and the Superfudge series, about a beleaguered nine-year-old boy, Peter Hatcher, forced to endure the irritations of having a younger brother. It was a scenario that spoke to me intimately. I, too, suffered the indignity of having a younger sibling, my sister Nell, so I turned to the adult who seemed to understand my feelings so clearly.

“Wrote a letter to Judy Blume,” I wrote in my diary on 28 June 1987. “I think she’ll make me feel good.” I posted it care of her publisher and waited for her to write back, which I assumed, with the confidence of a child, she would. I was right. Just two weeks later, I received my first proper letter in the post. Dated 6 July 1987, on Blume’s personalised stationery, it started as a simple form letter, advising me to talk to a professional and to hang in there. But at the bottom, there was a handwritten note from Blume herself:

Hadley –

I think you have a fabulous name! All siblings (sisters & brothers) have feelings like you and Nell. It’s normal. It’ll be OK. Don’t worry.

Love, J

Blume’s reply to Freeman’s fan letter, in 1987. Photograph: Hadley Freeman

The letter pleased me so much, I stuck it in my diary. But it was decades before I realised how extraordinary it was that one of the most successful authors ever took the time to write to me.

To reach Blume today, I fly to Miami and then take a little plane to Key West, a small island off the southernmost toe of Florida, where chickens roam free and people get around on cheerfully coloured bicycles. Blume had asked me to come a day early, so she and her husband, George Cooper, a writer and former law professor, could take me out to dinner. She also instructed me to call her as soon as I landed, because she was worried how I’d cope with the long journey from London. (To describe this as unusually solicitous behaviour from an interviewee to a hack is like describing Blume as a mildly successful writer.)

“I feel terrible about dragging you all this way to this funky place!” apologises the perky voice on the phone, as though I had walked on nails to a war zone. “How are you feeling? You must be so tired! I feel terrible!”

Later, she and Cooper drive over to my B&B in their Mini Cooper convertible, to pick me up for supper (they’re both tickled that his surname is written on the back of the car). Blume, wearing a T-shirt and three-quarter-length trousers, gets out of the car and gives me a big hug, followed by a pink baseball cap to protect me from the Floridian sun. Her pretty, pixie-like face, framed with a mass of brown curls, shines with warmth.

She taught me about menstruation, masturbation and making out – which is a damned sight more than any teacher ever did

Cooper and Blume live in Key West most of the year – the rest of the time, they’re in their apartment in Manhattan or visiting their children around the country (Blume has two from her first marriage, Cooper has one). There is a sweetly flirtatious manner between them, even after 30 years of marriage. Both 77, and trim and spry, they are a testament to the benefits of outdoor, warm-weather living. The day before I arrived, Cooper won a medal in a mini triathlon, which makes Blume clap her hands with pride in the retelling. She does physical exercise almost every day – including, pleasingly, tap-dancing classes – and has the easy grace of someone who can touch her toes without much trouble. Cooper, calm and steady to Blume’s energetic sparkiness, is an eloquent guide to Key West, but Blume is shifting impatiently in the back seat.

“Show her the cinema, George!” she says.

“You want to see the cinema?” Cooper asks, turning to me.

“You’ve got to see the cinema!” Blume replies for me.

We pull up in front of the beautifully retro Tropic Cinema.

“George built this!” she says proudly as we walk in, Cooper’s hand fondly on Blume’s lower back.

Cooper was part of the committee that founded the Tropic just over a decade ago. One of the auditoriums inside is called the George in his honour, and the main atrium is the Rudy and Essie Sussman Lounge, named after Blume’s parents.

“That’s my mother and father!” Blume tells an usher inside, in the lobby, pointing at a black-and-white photo of a couple on the wall.

“Oh, right,” the usher says, a little nonplussed.

“Don’t they look terrific?” Blume muses, clutching my arm.

***

Judy Blume has been thinking a lot about her parents recently. For the past five years, she’s been working on her fourth novel for adults, In The Unlikely Event. Set in her home town, Elizabeth, New Jersey, the novel takes place largely over the course of a few months in 1951-1952, when Blume was 13. Although the characters are fictional, she has incorporated into them various details about her parents: one is a dentist, as her father was, and the “diet doctor” her mother frequented makes an appearance. Today, Blume laughs at her memories of him: “His office was like a candy store! He would put the pills in a paper bag, 16 turquoise, 16 pink, 16 yellow. They gave her terrible diarrhoea.”

The novel is ostensibly about an extraordinary period when three planes separately crashed into the town, which Blume remembers, although her parents tried to protect her from the worst of it. But it is more fundamentally about life in 1950s America: how men and women, still recovering from the impact of the great wars, were hamstrung by social mores; how young women’s lives were governed by a fear of pregnancy; how children tried to make sense of a world shaped by a fear of communism, atomic bombs and war.

Her new novel is about life in the 1950s, and how children tried to make sense of a world shaped by fear of atomic bombs

“I’d always thought of my teenage years in the 1950s as so bland, but writing this book, I feel completely differently,” she says over supper in a restaurant on the beach. “Look at all the stuff that was going on in the world then! This book has been such a fascinating project for me.”

The book will also be Blume’s last novel. “I’m not doing a Philip Roth thing,” she says, referring to Roth’s announcement of his retirement from writing. “Because I know that I will write – I think I have to, you know, and I have some ideas about a memoir from birth to 12. But I know I’m not doing this again. I have told the stories I needed to tell.”

The next morning, we meet at a local restaurant for blueberry pancakes (despite having the proportions of a bird, Blume eats like a pro). Afterwards, we go to the home she shares with Cooper, an extraordinary 1950s build with a magical garden of banyan trees and orchids that seem to grow both in and out of the house. She proudly shows me huge files of research she did for the book, detailing everything from period radio shows to transcripts of survivors of the plane crashes. Like the A-grade student Blume once was, she loved doing the homework. “I’d say to George, ‘This researching is the best fun I’ve ever had!’ And he’d say, ‘Yes, Judy, but you still have to write it.’ And I always struggle with the writing.”

This seems astonishing coming from a writer who, at her productive peak in the 70s, was publishing two books a year, sometimes three. But Blume never intended to be a writer. As a child, she dreamed of being an actor, cowgirl or detective, just like the eponymous heroine of Starring Sally J Freedman As Herself (1977), which Blume describes as “my most autobiographical book”. Like Sally Freedman, Judith Sussman (as Blume was born) grew up in New Jersey in a middle-class Jewish family, an imaginative child desperate to know more about the adult world.

“I was so curious, I used to look in the little trash bins in public women’s rooms, dying to see blood. And I found it many times. Exciting!” She grins.

The family moved to Florida briefly for her older brother’s health (he had a serious kidney infection) and, years later, when she and Cooper started coming to Key West, Blume would look up at the starry sky and think happily, “This is the sky I looked on as a child.”

“I even have the same bicycle!” she laughs, pointing out a bicycle outside, painted as brightly as a child of 10 could ever wish.

Facebook Twitter Pinterest ‘I think the child I was until 12 was so much more interesting than the teenager I became.’ Photograph: Jeffery Salter/The Guardian

She has always preferred to write about children than teenagers, she says, because “I think the child I was until 12 was so much more interesting than the teenager I became. As a teenager, you get wrapped up in your friends and sexual stuff, and the imaginative life you had, it just goes. And mine was so rich and fun. Fortunately, I was able to tap back into that later on [through my books] to save my life.”

When Blume was 21 and a student at New York University, two events happened in the space of five weeks that effectively ended her youth: her father, whom she revered, died suddenly at the age of 54, and she married a lawyer, John Blume.

“It’s honestly like it was yesterday,” she says, referring to her father’s death, her voice cracking. “Everything they say a girl should get from her father in terms of total acceptance and love, I got all that from my father. But then I married a man just like my mother – so phlegmatic.”

Did it ever occur to her that she could stay single for a time after college? Blume gasps in mock terror: “That is so not the way it was done then.”

The life of a housewife made her wither inside. She'd dream of being a young woman 'with long swinging straight hair'

The Blumes lived in New Jersey and had a daughter, Randy, and a son, Lawrence, two years later. “I loved being pregnant and I loved having children, but I wasn’t happy then,” she says. The life of a suburban housewife made her wither inside. She would gaze across the river towards New York and dream of being a young woman “with long swinging straight hair”, marching for women’s rights. (“The neighbours thought I was crazy. The women’s movement was slow in coming to suburban New Jersey,” she says wryly.) Thwarted in that fantasy, she started to believe she was suffering from various illnesses: “Always exotic ones, of course.” She smiles. One day, she decided to write a little story.

The One In The Middle Is The Green Kangaroo was published in 1969, followed almost immediately by Iggie’s House, Are You There God, It’s Me Margaret, Then Again, Maybe I Won’t and Freckle Juice, all in the space of two years. Much has been made of Blume’s skill at treating important themes in her books for young people: racism in Iggie’s House, puberty in Are You There, God? It’s Me, Margaret, teen sex in 1975’s Forever, the death of a parent in 1981’s Tiger Eyes, which Blume says was subconsciously about the death of her father. But she says she never approaches her books in terms of themes; rather, she looks for “characters and storytelling: that’s what interests me, not literariness”. This does mean that her adult novels – Wifey, Smart Women, Summer Sisters, In the Unlikely Event – while always enjoyable, can feel a little soapy. But when she wrote about, for example, menstruation in Are You There, God? It’s Me, Margaret, she did it because she remembered what it was like to be a little girl who wanted to know about things that grownups wouldn’t talk to her about, “and that feeling of being desperate for information – I remembered it so well. And thank God, because I so needed a creative outlet.”

Facebook Twitter Pinterest At a book signing, with sixth-grade students, in 1977. Photograph: Jane Tarbox/Getty Images

What is most striking about Blume’s books for children, rereading them as an adult, is how brilliantly she captures the mindset of a young person, whether it’s nine-year-old Peter in Tales Of A Fourth Grade Nothing or 18-year-old Katherine in Forever. To read Blume’s books as a child is to feel as if an adult finally understands you; to read them as an adult is to remember exactly how you felt at those ages.

It is also remarkable, these days, to read books for young people featuring such resolutely normal characters. When I read Blume’s books as a kid, they taught me that a child like me – wholly devoid of magical powers – was worthy of being the star of her own story. In the past, Blume has been a little dismissive of the Twilight series, but she says over our breakfast pancakes that she doesn’t want to cause a fuss on Twitter. When I raise this, she grows quiet and tries to change the subject.

Has she noticed that kids today have a greater interest in superheroes? “Yes, that’s true. I now get asked by children, ‘What would your super power be?’ That never used to happen. I always think, I don’t want to answer that question.”

Like superheroes, fame had a different quality when Blume started writing, and she wasn’t aware of any media attention until the late 70s. What did her husband make of her new career? “He really didn’t care,” she says. “He’d say things like, ‘Paper and pencils are cheap, so fine, as long as everything else gets done.’ He was a 50s kinda guy, you know.”

In 1972, Blume wrote It’s Not The End Of The World, about a 13-year-old dealing with her parents’ divorce, and dedicated it to her husband John. In 1976, they divorced. Does she think the confidence she got from writing that book gave her the confidence to leave? “Yeah. I do,” she says quietly.

Almost immediately after her divorce, with two teenagers in tow, Blume married for the second time, this time to a physician and journalist. “Ay-yay-yay – I don’t know what I was doing then. I was crazy. I was very lonely. I was very sad. Maybe I was fearful, maybe I was looking for something and I wasn’t brave enough to do it on my own, because I didn’t even know what it was,” she says. The marriage lasted only two years, but in that time she wrote Starring Sally J Freedman and Wifey, her first book aimed at adults, which tells the story of a woman who wants to leave a stultifying suburban marriage.

Was she trying to make sense of her own life? Blume sighs. “It’s hard for me to self-analyse. I prefer to think, ‘Oh, aren’t I lucky?’”

This determinedly optimistic nature, coupled with her 50s-influenced fear of being single, probably explains how she fell into a relationship with the man who would become her third husband, George Cooper, before the paperwork on her second divorce was done. By this point, Blume was living in Santa Fe and the two were set up by Cooper’s ex-wife. They went on a date on Sunday night and by Tuesday Cooper had moved in.

“I was always looking for the right relationship, and I liked being married. I thought, ‘I know how to do this, I’m good at it!’” she says. “But once you find the right one, you can’t imagine how you… I would never jump again. I jumped with George, but I got lucky.”

They married in 1987, after seven years of living together, and since then Blume has written five books, including her latest – a remarkable drop in productivity. Whereas once she’d write a book in six weeks, now they take her several years. “I felt so much less pressure when I got happy… and it ruined my career,” she says. Working on In The Unlikely Event has been hard on them both: “He misses having me to himself. And, for me, it’s hard to be sexy when you’re always on a deadline.”

Facebook Twitter Pinterest Judy with her third husband, George Cooper, in 1984. Photograph: Charles Bennett/AP

We break for lunch and order a “Judy” pizza from a local pizzeria, topped with red and yellow peppers, courgettes, basil and spinach, and named in her honour. Of course, the real problem with slowing down in productivity means that Blume is still largely defined by books she wrote 40 years ago, and only occasionally does she show weariness with this, wincing a little when I refer to “Ralph”, the name a teenage boy memorably gives his penis in Forever. But in the main, she is a remarkably good sport. We talk a little about her support for Planned Parenthood, the pro-choice organisation, which has resulted in Blume receiving hate mail and requiring a bodyguard for some of her speaking engagements. She never got the long swinging straight hair, but Blume is, finally, very much part of the women’s movement. Is she worried about being in the public eye again? She thinks for a moment.

“No. No, I’m not. No,” she replies, with growing certainty.

After lunch, it’s time for the photographer to take pictures and, to give herself some energy, Blume puts on some songs from the 50s. One of my last sights of this indefatigable optimist is of her practising her tap-dancing moves next to her brightly coloured bicycle, singing along to Judy Garland’s Get Happy.

But there is one thing I need to do before leaving Florida. Reaching into my bag, I take out my letter from her, which I have kept for almost 30 years.

“Oh look, I wrote back to you!” she says, peering at it. “I didn’t always do that, you know.”

I assumed you wrote back to everyone, I say.

“Oh no, definitely not. Certainly not by 1987. There must have been something about your letter that got to me.” She looks up and smiles encouragingly: “You must have been quite a little writer back then.”

Three decades on, Blume still knows how to make her readers feel good.

• In The Unlikely Event, by Judy Blume, is published on 4 June by Picador at £16.99. To order a copy for £13.59, go to bookshop.theguardian.com or call 0330 333 6846.