Before you read this book, look at the photo of Zarah Ghahramani on the dust jacket. Throughout the harrowing narrative you will have her image fixed in your mind: a slender, pretty young woman with a Mona Lisa smile – and a victim of savage torture.

Ghahramani grew up with the new Iran of Khomeini, living a double life. Her father had been well placed in the government of Shah Pahlevi – not a slavish zealot to the Shah nor a member of his infamous secret police, but a sensible man who did his duty and who held his Islamic religion dear, but without fanaticism. Her mother was a Zoroastrian. Little Zarah learned by age six that she inhabited two worlds, that of home and family, a safe, generally happy world of childhood, and the outside world, where she was forced to act like everyone else, to accept the dictates of the rabid Shiite regime. She learned that she must always obey the regime no matter how outrageous their rules, and relax and smile only at home. The regime controlled everything. One day the schoolchildren were inspected; those who were wearing white socks instead of black were sent home, because a new rule said that wearing white showed disrespect for the Iranian army fighting against Saddam Hussein in a war that had lasted much of Zarah's young life. The regulations for women were naturally even more cruel and confining than those for men. If a woman was widowed by the war, she was forbidden to smile for the duration of the war and could remarry only by permission of the state. Smiling at her own children would be a crime. Such unfeeling laws created family rifts and kept everyone in a state of nervous stress.

Zarah's upbringing was liberal and though her family disapproved, she became involved in a dissident student movement by the time she started college. Her fiancé also objected – strenuously – and tried to force her to obey Shia law, for both their sakes. Zarah just couldn't do it, becoming more and more attached to a well-known revolutionary named Arash. Then, one day, she was arrested and taken to Tehran's infamous prison, Evin, where she was isolated in a dank cell and regularly tortured.

Zarah describes in frightening detail how the torture broke her spirit, and yet did not. At first there seemed to be a purpose to it: obviously her captors wanted her to sign confessions and give names of her fellow conspirators. They wanted her to give them information about Arash, who was also in prison. In fact, unknown to her, hundreds of her fellow students had been arrested. She never saw any of them. She was told with sadistic pleasure by her interrogator, that her mother came every day to Evin and was told by the officials that her daughter was not there.

The government produced photographs that made it impossible for her to lie. She was unable to resist signing whatever she was given. But the torture continued, day after day. Sometimes it was as senseless as a guard simply coming into her cell and beating her with fists and feet. During this interminable ordeal, Zarah retained some hope that her family and fiancé were taking steps to get her freed, and comfort from her recollections of the revolutionary words of great Persian poets, such as Omar Khayyam: "Almost every quatrain of Omar Khayyam's subverts the dogma of the mullahs, because his poetry is the work of an inquiring mind. You can't have an inquiring mind and talk about it publicly in Iran."

One morning early, she was dragged from her cell and covered in a heavy black chador. Knowing that women were often hanged in the morning after the first prayers, and always wearing a chador, she began to fantasize the worst and to prepare. She decided that if there were any more torture, she would find a way to die.

Zarah's book, written with the assistance of Australian Robert Hillman, has a resolution: we know that ultimately she was freed and able to leave Iran. The feelings that she expresses in her book give a sense of the commonality of imprisonment and torture – the hopeless frustration, the constant pain and fear, the tiny joy in small incidents, the odd but desperately important bonds with other prisoners, and the guarded relief that comes with release.