Best-selling authors including Ian Rankin, Val McDermid and Lee Child have condemned "fraudulent" writers caught praising their own work on Amazon.
The trio, who have sold millions of novels between them, signed an open letter attacking the use of "fake identities".
It comes after crime writer RJ Ellory apologised for a "lapse of judgment" after he was caught praising his own work and criticising other novelists under an assumed name on the bookselling site.
Ian Rankin: one of the author's to condemn RJ Ellory and 'sockpuppeting'
Another thriller writer, Stephen Leather, has also admitted using different online identities- known as sockpuppets - to publicise his work.
Today's letter, which was also signed by Mark Billingham and Jo Nesbo, said it was "likely that other authors are pursuing these underhand tactics as well".
It went on: "These days more and more books are bought, sold, and recommended online, and the health of this exciting new ecosystem depends entirely on free and honest conversation among readers. But some writers are misusing these new channels in ways that are fraudulent and damaging to publishing at large."