JK Rowling's crime debut has gone on to top sales charts after it emerged she had secretly written the novel under a false name.
She was outed as the writer of The Cuckoo's Calling at the weekend, having published the book as Robert Galbraith.
But since it was revealed she had been behind the book sales have rocketed, propelling the hardback to the top of the Amazon bestseller chart while the digital version is at number one in the iBooks chart.
Despite the book being written under a different name, The Cuckoo's Calling - about a war veteran turned private investigator called Cormoran Strike - had drawn acclaim from reviewers, although it had shifted just 1,500 copies since it came out in April.
She was rumbled after the Sunday Times looked into how a first-time novelist could produce such an assured debut work.
After being exposed she said: "I hoped to keep this secret a little longer, because being Robert Galbraith has been such a liberating experience.
"It has been wonderful to publish without hype or expectation and pure pleasure to get feedback from publishers and readers under a different name."
The book was published by Sphere, part of Little, Brown, which published her last novel, The Casual Vacancy.
Rowling has now indicated she will write further books in the series.
"To those who have asked for a sequel, Robert fully intends to keep writing the series, although he will probably continue to turn down personal appearances," she said.
A spokesman for Waterstones said: "This is the best act of literary deception since Stephen King was outed as Richard Bachman back in the 1980s.
"Before The Casual Vacancy was published, the general suspicion was that JK Rowling might write a crime novel: turns out we were right! This is a wonderful summer surprise for readers and booksellers everywhere."