It had been a restless month for "Fifty Shades" fans since E.L. James announced a new book joining the trilogy over Twitter. The new book, entitled "Grey,"  retells the happenings of the first book from Christian Grey's point of view.

International Business Times reports that over one million copies of "Grey" had been sold in four days. However, the massive number is not surprising at all, when compared to previous books in the series.

The Telegraph reported that the first book had become the best-selling book of all time in Britain with 5.3 million copies sold, surpassing Harry Potter's records.

According to the report, Random House, the publishing company that took over the publication of the trilogy, said the combined sales of the trilogy goes over 12 million physical books and ebooks.

Publishers Weekly reported that the entire trilogy had sold over 10 million in the United States, just after the release of the final book.

As of today, BBC reports that the "Fifty Shades" trilogy had already sold over 125 million copies worldwide since 2011.

On June 15, Random House reported a missing copy of the finished manuscript of "Grey." BBC notes that the police found no evidence that a crime had taken place.

"We are delighted that the book's theft does not appear to have been for any malicious intent or financial gain," said Random House in a statement.

In "Fifty Shades of Grey", which is the story retold in the new book "Grey," young billionaire Christian meets literature student Anastasia Steele in his office for an interview.

When Grey proposes a BDSM relationship, Ana makes a decision that changed her whole life, and the lives of millions of readers across the globe.

What makes the Fifty Shades trilogy unique, besides the hot erotic scenes and rides with Grey's helicopter Charlie Tango, is the relationship problems and issues of the two.

From Ana's point of view, Christian showed his different sides but remained mysterious. There was sweet Christian, caring Christian, thoughtful Christian.

However, he had darker sides as well - Christian who had a dark past, Christian who had commitment issues, Christian who didn't like to be touched.

As of now, millions of readers are swooning over Christian's thoughts on the moment he met Ana and how he fell in love.

Four years after the release of the first book, readers can now plunge deeper into the fifty shades of Grey.