At Barnes & Noble bookstore in Manhattan, where James was appearing at a book signing on Thursday, the line stretched around the block.
“Grey” was the highest Kindle pre-order book of the year on Amazon.com when it was released as an ebook at midnight and was expected to be an instant bestseller.
Publisher Vintage Books, a division of Knopf Doubleday Publishing Group, supplied a million copies of the novel to bookstores.
James, who dedicated the novel to fans who asked for a book told from the perspective of billionaire Christian Grey, said it was not difficult to write.
“I thought it would be hard but once I found his voice it was actually quite easy. Like any man, he is not observant, at all,” she said in an interview on the “Today” early morning news show.
In the novel, James gets into the mind of the handsome 27-year-old business tycoon with a penchant for kinky sex, who introduces naive college student Anastasia Steele to sadomasochism and bondage.
The novels have been dubbed “mommy porn” for the fantasy they provide for their millions of fans.
Early reviews of “Grey” say the book holds nothing back in revealing Grey’s deepest desires and secrets.
“While action-hungry fans will be thrilled by the more graphic sex scenes, romance lovers will finally get the answers they’ve been craving,” said Britain’s Daily Mirror newspaper.
Adrian Liang, senior book editor at Amazon.com, found the second half of the novel, when Grey gets into his emotional problems, the most engaging.
“I think this is a stronger book because Christian is a more complex character,” she said in an interview. “I think E.L. James has definitely rose to the challenge of writing a more complex story and her writing style has improved quite a bit since the first book.”
“Fifty Shades of Grey” was turned into an R-rated film by Comcast Corp-owned (CMCSA.O) Universal Pictures starring Dakota Johnson and Jamie Dornan, grossing more than $500 million at the global box office since its February release.
Film adaptations of the second and third books are planned.