British author E. L. James has reportedly accumulated a net worth of £37 million ($58 million) from her steamy "Fifty Shades of Grey" trilogy.   

Originally a set of fan fiction posts based on the characters of "Twilight", a bestselling paranormal young adult series, "Fifty Shades of Grey" has become one of the most popular books despite the copious amount of sex and its depiction of the BDSM lifestyle.

James has become the fourth wealthiest author, toppling romance novelist Jackie Collins into fifth place while "Harry Potter" scribe J. K. Rowling remains at the top spot, according to Yahoo News UK.

Despite getting generally negative reviews, with most critics noting its lack of any literary merit, the book remains popular among readers, especially women, as the book focuses on female desire, helping them relate to things they would not normally share with others.

The film itself was also panned by critics, but was a box office hit and the second highest grossing release of the year. Erotica authors on the other hand, lauded the book for bringing the erotica genre into the mainstream, according to The Guardian.

Literary analysts credit its popularity to its time-tested formula of boy-meets-girl that has been proven effective in erotic novels in the past. Timing and marketing are also factors attributed to its success, and the old adage that "sex sells."

James is expected to notch up her spot in the literary rich list in the future once the second and third film adaptation of her trilogy hit the screens.  

The erotic trilogy tells about the intimate relationship between Anastasia Steele, a college graduate, and Christian Grey, a business tycoon, as they take readers in the world of bondage, discipline, sadism and masochism.

The reported figures do not include any royalties from the 2015 "Fifty Shades of Grey" film, which catapulted Jamie Dornan and Dakota Johnson into fame, with the film grossing at £360 million, according to The Telegraph.