Miami - Young school teachers, middle-aged nurses and even the elderly flocked to a Miami book store on Sunday for a chance to meet the author of the bestselling erotic romance Fifty Shades Of Grey at the launch of her US book tour.

British newcomer E.L. James drew more than 500 men and women at a morning book signing and is scheduled to speak later before a sold-out crowd at the historic Biltmore Hotel. It was her second-ever book signing, yet the size of the crowd snaking through the store with mimosas and books in hand drew comparisons to the response seen with writers like Anne Rice and even politicians.

“This is a literary phenomenon,” said Mitchell Kaplan, owner of Books & Books, the independent bookstore where James was signing copies. “E.L. struck a nerve, and her storytelling speaks to so many people.”

In a few short months, James has snagged a seven-figure contract with Vintage Books. Universal Pictures and Focus Films have purchased the rights to all three books in the trilogy about an unworldly college student who begins an unusual romantic relationship with a wealthy young businessman. The books have been called “mommy porn” for their sexual content and large, mostly female following, though men were lining up for autographs as well.

“I read it through lunch breaks and I'm giggling,” said Laura Vargas, 31, an executive assistant at a large insurance company. “I'm like, 'I can't believe she just wrote that’.”

James began writing the books as fan fiction to Stephenie Meyer's Twilight series and quickly developed a cult-like following of her own. The romance between Anastasia Steele and Christian Grey is surprising because of its unconventional erotic nature: Grey asks Steele to sign a contract, agreeing to be his “submissive” and to partake in a range of erotic activities. The stories were first published online, and as word of mouth spread, droves of people - many of them not traditional readers of romantic or erotic fiction - began downloading them on iPads and Kindles.

“I'm staggered by this,” James said in an interview with The Associated Press. “I never set out to do this.”

Until recently, the affable, laid-back author had been mostly preoccupied with her work as a television producer and as the mother of two teenage boys. She was born and raised in London, studied history in college and dabbled once in a while with writing, but never spent a large amount of time on it until coming across the Twilight books.

“I tried a couple of times, but never thought I could,” James said of writing fiction.

Even now, she's not sure she'll be able to write another.

“It's really quite daunting,” she said.

A broad swathe of mostly women, of all ages and backgrounds, showed up on Sunday at the bookstore in Miami's Coral Gables neighbourhood, a family-oriented, upper-class enclave of the city. A young server went around with a tray of bright-coloured drinks, and fans exchanged giddy stories about their experience reading the books.

Mayreny Objio, 33, a teacher, said the books have taken her work colleagues by storm. They talk about who should play Christian Grey in the movie and his dominant nature. She read all three books in a week and brought her husband to the signing, encouraging him to read them, too.

“I think couples should read it,” Objio said. “It will bring a lot more spice. It's something different.”

Emilia Diaz, 57, an aesthetician, said it was a man who introduced her to the books. They had been talking online and over the phone for months and finally agreed to meet in person. On their first date, he suggested she read the books.

“Maybe he wants you to be his submissive,” joked her cousin, Sandra Sousa-Druckman, an interior designer.

Diaz came in a group of four women, the eldest being Sousa-Druckman's 87-year-old mother, Cathy Perkins. Perkins, who was married for 60 years, said she usually reads Danielle Steele but wants to take up James' trilogy next. She had a copy of the second book, Fifty Shades Darker, for James to autograph.

Stephanie Madison, 59, a bioterrorism co-ordinator at Jackson Hospital, said her boss had recommended the books to her. She then approached her daughter, Chantele Cogdell, about buying her a copy for Mother's Day.

Cogdell, who works in medical billing and coding, went online to find out what the book was about. Cogdell usually buys her mother flowers, purses or gift cards.

“I said, 'You really want this?’” Cogdell recalled.

Her mother enthusiastically replied: “Yes!”

Anne Messitte, the publisher of Vintage Books, said the overwhelming response to James' second book signing, and the first in her tour, was unprecedented for a new writer.

“I think at the heart of it, these are wonderful, modern stories that engross the reader,” she said. “They're page-turners.” - Sapa-AP