“Fifty Shades of Grey: that was where I lost my rag,” says Caitlin Moran, feminist, Marxist, critic, columnist, comedian and author of the British bestseller How to Be a Woman (2012).

When Moran gets angry, she takes action. “I think it’s very important that women own their sexuality—not a man comes along and discovers it for her, but they discover it themselves. I think there’s very little that’s more dangerous and brilliant in this world than a young woman who knows how to please herself sexually, is in control of herself sexually, and wants to work hard and earn her own money and be independent in her way in the world. Something like Fifty Shades of Grey—where she’stotally financially and sexually reliant on a man—is so the antithesis of everything I believe, everything that I want my teenage girls to [seek out] in their future, that I sat down and wrote a book!” she says.

The monologue ends with a comic flourish—but she’s serious about the book. How to Build a Girl is the empowering, sex-positive story of Johanna Morrigan, a lovely, pudgy teenage girl growing up poor in Wolverhampton, England. Her father is a frustrated musician on the dole, her mother is exhausted, and her four siblings are a motley assortment of co-conspirators and floppy babies. From the cramped quarters of council housing, Johanna yearns for a better, sexier life—one she has every intention of claiming for herself.

“But I don’t want to be noble and committed like most women in history were—which invariably seems to involve being burned at the stake, dying of sadness, or being bricked up in a tower by an earl. I don’t want to sacrifice myself for something. I don’t want to die for something. I don’t even want to walk in the rain up a hill in a skirt that’s sticking to my thighs for something. I want to live for something, instead—as men do. I want to have fun,” Moran writes.

To that end, “I am currently writing a book, in the endless, empty hours of the day. It’s about a very fat girl who rides a dragon around the world and through time, doing good deeds,” she writes.

Writing does prove to be Johanna’s opportunity up and out (though not specifically the bit about the dragon). After winning a television appearance and cash prize for a vaguely romantic poem about the family dog, she realizes she might, at age 16, begin to make her own living. Educating herself with borrowed tapes from the public library, she begins mailing an album review a day to a popular music magazine under the nom de plume Dolly Wilde, borrowed from a scandalous lesbian relation of Oscar’s. She’s invited to London and hired.

To this point, her trajectory is not unlike the author’s own: At age 16, Moran was a prizewinning essayist, published novelist and journalist for Melody Maker magazine. However, Johanna’s metamorphosis into bold Dolly, a biting critic and self-proclaimed “lady sex pirate,” more closely resembles New Musical Express journalist Julie Burchill, she claims. (“[Burchill] was the biggest star of the time in print—more famous than the bands,” she says admiringly. Whereas, in describing herself, Moran says: “I’m a bit shy, and I secretly like Fleetwood Mac.”)

Spirited Dolly fakes it till she makes it, bringing the can-do spirit to feature stories and sexual exploits alike. “Blow jobs are, mythically, what all boys want the most—and so, again, as a good student of market forces, I am very interested in them,” she writes, for example.

Her candor is enviable and inspiring. “She doesn’t know you’re supposed to be ashamed of a lot of things. She’s innocent in her shamelessness, she doesn’t really know you’re supposed to be ashamed of your sexuality, and she wants to be good and she wants to be noble; she wants to be a genius, she wants to change the world, but yet…she’s horny; she’s a sexual humanitarian, basically, and all the way through she never ever once has self-loathing about being fat. She just cracks on with it, and she never gets turned down for a shag because she was fat, because in real life that doesn’t happen either. It’s amazing how many women have been fat-shamed in their existence in society when in the actual world people go out there and have just as much sex and just as much fun when they’re thin as when they’re fat: Fat teenage girls out there, I have been out there and I can tell you, your life will be the same as your thin cousins, it’s absolutely fine,” she says.

Megan Labrise is a freelance writer and columnist based in New York. Follow her on Twitter.