"Britney Spears knows what it's like to feel trapped: First by poverty, then by fame, then by her family.
The Woman In Me, which is published on Tuesday, lifts the lid on her 13-year conservatorship.
She has been subject to scrutiny and ridicule throughout her life. As a teenager, journalists repeatedly asked her questions about her breasts and her sex life. As an adult, she was imprisoned under a conservatorship that stripped her of some of the most basic human rights.
For 13 years, she could not see her two sons without approval. Her driving licence was confiscated. She could not choose her meals, and was forbidden from drinking tea or coffee. When she wanted to have a contraceptive intrauterine device (IUD) removed, her request was denied.
That court-imposed order, overseen by her father, was lifted two years ago, when a judge ruled Spears could make her own decisions again.
But her new memoir, The Woman In Me, reveals that was no happy ending...
Those events cast a shadow over Spears' life story. Along the way, every betrayal and public indignity feels like a step along the path to her eventual incarceration.
It began as soon as she exploded onto the pop charts in 1998. She was an overnight sensation, but the press refused to believe she had any agency. Her songs were written for her, they noted, while suggesting that her public image was created by creepy, salivating older men.
The more she was perceived as a product and a pawn of the music industry, the easier it became to erode her autonomy.
In one of the book's most chilling moments, Spears recalls her father telling her he's assumed legal control of her personal and professional affairs.
His words: "I am Britney Spears now."
The early chapters of the book stress how much people underestimated her.
Spears may not have written her music - but when she was given ...Baby One More Time, she stayed up all night to make sure her voice was "fried, and "gravelly", enhancing the song's yearning maturity.
And when it came to shooting the video, the 16-year-old rejected the original pitch - in which she'd have been "a futuristic astronaut " - and insisted on a high school setting with dancing in the corridors, just like Grease.
Both decisions were crucial to the song's success - but no-one was willing to accept a blonde teenager from a Louisiana trailer park could outsmart the collective brilliance of the music industry.
"No-one could seem to think of me as both sexy and capable," she writes. "If I was hot, I couldn't possibly be talented."
Although she exercised creative control behind the scenes, Spears' publicists infantilised her.
She was marketed as a chaste, God-fearing country girl - even though, she writes, she had been a regular smoker since the age of 14 and lost her virginity around the same time.
At first, however, she toed the PR line...
Eventually, however, Spears' innocent image set her up for a downfall.
In one of the book's most harrowing sequences, she talks about having a medical abortion during her relationship with Justin Timberlake. The pills she had been prescribed left her in agony but the couple were too scared to visit a hospital in case the news leaked. For hours, Spears was curled up, "sobbing and screaming" in pain on the bathroom floor.
"Still, they didn't take me to hospital," she says. Instead Timberlake, "thought music would help, so he got his guitar and lay there with me, strumming it."...
After their separation, she was vilified in the press, with Timberlake strongly hinting she had cheated on him (she says it was the other way round, with "one of the girls from All Saints").
Timberlake has yet to respond to his depiction in the book.
The couple's break-up only increased the appetite for gossip about Spears' personal life. The tabloids hounded her. She recalls a photographer from People magazine demanding she empty her handbag, so they could check whether she was carrying drugs or cigarettes.
Eventually, the pressure became too much. In 2007, reeling from the death of her aunt Sandra and suffering from post-partum depression, Spears marched into a hair salon, picked up some clippers and cut off her hair.
"Shaving my head was a way of saying to the world: [Expletive] you," she writes.
"I'd been the good girl for years. I'd smiled politely while TV show hosts leered at my breasts, while American parents said I was destroying their children by wearing a crop top. And I was tired of it."
We all know what happened next. Instead of being seen as an act of strength or rebellion, Spears' buzz-cut was used as evidence of instability.
Within a year, she had been placed under the conservatorship.
Spears is a straightforward writer. She doesn't embellish or decorate her prose. That matter-of-fact style amplifies the horror of those years.
She talks about being pinned down on hospital stretchers and forced to take medication against her will. At home, she isn't allowed to take a bath in private. Boyfriends are vetted and informed of her sexual history before they can go on a date.
At first, she tries to appease her parents and the doctors. "If I play along, surely they'll see how good I am and they will let me go," she says.
When she considers rebelling, access to her two young sons is used as a bargaining chip.
"My freedom in exchange for naps with my children... was a trade I was willing to make," she admits.
But even while she was supposedly incapable of looking after herself, Spears was sent out on tour, hired as a judge on X Factor and booked for a four-year Las Vegas residency.
The singer, who used to collect receipts in a glass bowl in order to keep track of her taxes, carefully documents the millions everyone else made from those engagements, while she was given a strict allowance of $2,000 (£1,635) per week.
Losing all sense of self, she almost gave up.
"The fire inside me burned out," she recalls. "The light went out of my eyes." ...
It's impossible to read The Woman In Me and not feel sad and outraged on Spears' behalf.
One tiny detail of her new life, in particular, emphasises how grey her world had become. "Now," she writes, "I get to eat chocolate again".
Spears' story is told with the same approachable warmth that made her a star. And, outside the defining events of the last 15 years, she spins a good yarn - whether describing her pregnancy cravings (food and sex, apparently); or reliving her terror at dancing with a snake at the 2001 MTV Awards.
Her family aside, there are no real villains or scandals to be uncovered. But nor are there any great revelations about Spears' music or inner life.
What we are left with, not for the first time, is a cautionary tale about fame and the corrupting influence of money. And, just maybe, a glimmer of hope for a woman whose adult life has been dictated by others.
"It's time for me not to be someone who other people want," she writes. "It's time to actually find myself."
