It's had a major impact on the publishing world - and in quite a few bedrooms.
But now Fifty Shades Of Grey is at the centre of an unusual court case in the UK.
A man is being divorced by his wife after he refused to spice up their love life by reliving scenes from the erotic bestseller.
The wife, a 41-year-old banker claims her husband's "boring attitude" to sex is evidence of "unreasonable behaviour".
In her grounds for divorce, filed at the High Court, she refers to the novel, which tells of the sadomasochistic affair between billionaire Christian Grey and naive student Anastasia Steele. The woman in the court case bought the raunchy book almost as soon as it was published last year and hoped it would encourage her husband to be more adventurous in bed.
She bought some sexy underwear but her husband failed to respond to her advances and he even blamed her behaviour on 'that bloody book'.
Now she has petitioned for divorce citing his alleged low libido as evidence of "unreasonable behaviour", one of the five grounds for divorce under English law. The wife's solicitor, Amanda McAlister, a family law expert, believes the case is the first where the new phenomenon of 'mummy porn' has triggered a divorce.
"The woman had been reading the book and wanted to spice up her love life," McAlister said.
"She thought their sex life had hit a rut - he never remembered Valentine's Day and he never complimented her on her appearance. So she bought sexy underwear in an attempt to get her husband more involved.
"She said, 'Let's make things more interesting'.
"But when he still didn't take any notice she told him he had a boring attitude to sex and she was fed up.
"He went ballistic when he found out the name of the book she was reading and told her, 'it's all because you have been reading that bloody book'."
The husband is admitting "unreasonable behaviour" so the divorce can be granted quickly without a contested hearing in which his alleged low libido would be discussed in court.
McAlister claims the case is evidence of a social change where women have been encouraged to become more adventurous in the bedroom.
"There has been a real shift in sexual attitudes," she said.
"It used to be the men who complained they weren't getting enough nookie in the bedroom.
"But now it's the women who are calling their husbands boring after reading books like Fifty Shades.
The novel is the first in a trilogy by British author EL James which have sold more than 60 million copies worldwide.
James, whose real name is Erika Mitchell, describes her books as "romantic fantasy" stories that offer women a "holiday from their husbands".
- DAILY MAIL