Erotic novel Fifty Shades of Grey continues to break records in the UK and its resounding success has led to a rise of copycat books.
EL James's book has broken the record for the fastest selling paperback in the UK and sold 205,130 paperback copies in one week alone.
That figure is 64,000 more than the previous record set by Dan Brown's The Lost Symbol in July 2010.
EL James has also become the first author to have two or more books sell more than 100,000 copies in the same week.
Fifty Shades of Grey has gone on to sell 765,000 copies in just two month. The previous biggest-selling paperback of all time, Brown's The Da Vinci Code, took six months to sell that many.
It is expected James's book will have sold one million copies by the end of the month.
Philip Stone, charts editor of the Bookseller, said: "Sales of the Fifty Shades series have been nothing short of phenomenal and records are tumbling.
"Of course this is just sales of the physical, print edition. It is no doubt breaking e-book download records too, meaning Fifty Shades Of Grey is perhaps the fastest-selling adult novel of all time."
The huge success of the book, as well as the other two in the trilogy, Fifty Shades Darker and Fifty Shades Freed, has led to the inevitable rise of similar books as publishers hope to cash in on the phenomenal success of James's 'mummy porn'.
Some of the books have either been republished, such as 12-year-old S+M title Haven of Obedience, or been written in quick time I order to hit the shelves as soon as possible.
One of the latest erotic books is from a series by US author Sylvia Day called Bared to You, which is already available as an ebook and will arrive in paperback form in July.