Ms Cojean investigated Gaddafi's abuses of power after meeting Soraya (her name has been changed), who Gaddafi kidnapped when she was 15 and held for five years as a sex slave.
Sonaya says she was violently raped, beaten and abused on an almost daily basis and saw similar abuse of other girls and boys.
Telling her story, Soraya said while at school in the coastal town of Sirte, she had been given the 'honour' of presenting a bouquet of flowers to Gaddafi during a visit in 2004.
After presenting the flowers, Gaddafi, who had eight children, patted her head. She said this was a symbol to his aids that he wanted her.
The following day she was summoned to his palatial six-mile long compound near Tripoli, Bab al-Azizia, where she was stripped, shaved and taken to Gaddafi.
She said he was lying naked on the bed and tried to rape her.
When she fought him off, Soraya was taken away by head of the harem Mabrouka for 'lessons'.
She is quoted in the book as saying: 'He grabbed my hand and forced me to sit next to him on the bed. I didn't dare look at him.
'He said, "Don't be afraid. I'm your papa. That's what you call me, isn't it? But I'm also your brother and your lover. I'm going to be all that for you. Because you are going to stay and live with me forever."'
The schoolgirl was given porn to watch and was made to watch Gaddafi have sex with others so she could 'learn'.
Boys and his male guards were also raped by the tyrant, according to the book.
Soraya was eventually allowed home in 2009 but she says she is a shame to her family because she had sex outside marriage.
She said she only felt free from Gaddafi after his death in 2011 at the end of the civil war.
The book also features interviews with a woman who ferried the girls to Gaddafi's compound and other victims.
Ms Cojean also alleges Gaddafi, who was married to Safia Farkash, pursued students and the wives of foreign dignitaries.
Ms Cojean was quoted in the New York Daily News as writing: 'It was not so much about seducing a woman as, through her, humiliating the man who is supposed to be responsible for her.'
Female visitors were routinely subjected to blood tests by Gaddafi's nurses to make sure they were disease free in case he wanted to have sex with them.
Marie Colvin, the Sunday Times journalist killed in Syria in 2012, reported that a nurse had approached her with a needle when she was in Tripoli to interview Gaddafi. She declined to give blood.