Amazon.com, the world's largest online retailer, is no longer selling a book that bills itself as a guide for paedophiles.
It was not immediately clear whether Amazon.com pulled the item or if the author withdrew it himself.
The book, The Paedophile's Guide To Love And Pleasure: A Child-lover's Code Of Conduct, offers advice to paedophiles on how to make a sexual encounter with a child as safe as possible.
It includes first-person descriptions of such encounters, purportedly written from a child's point of view.
The availability of the book calls into question whether Amazon has any procedures - or even an obligation - to vet books before they are sold in its online stores.
The title is an electronic book available for Amazon's Kindle e-reader and the company's software for reading Kindle books on mobile phones and computers.
Amazon allows authors to submit their own works and shares revenue with them.
Amazon issues guidelines banning certain materials, including those deemed offensive. However, the company does not elaborate on what constitutes offensive content, saying it is "probably what you would expect." Amazon also does not promise to remove or protect any category of books.
Once discovered yesterday, the book triggered outrage from comentaters on sites such as Twitter. Some people threatened to boycott the online store until Amazon removed the book. Two petitions on Facebook won more than 13,500 supporters.
Yesterday, child online safety advocacy group Enough Is Enough says it was not surprised someone would publish such a book, but that Amazon should remove it. It said selling the book gives the impression that child abuse is normal.
But Christopher Finan, president of the American Booksellers Foundation For Free Expression, said Amazon has the constitutional right to sell any book that is not child pornography or legally obscene. Mr Finan said Greaves' book does not amount to either because it does not include illustrations.
This is not the first time Amazon has sold material that promotes illegal activity. It is accepting pre-orders for the hardcover version of I Am The Market: How to Smuggle Cocaine By The Ton, In Five Easy Lessons by Luca Rastello.
Nor is it the first time Amazon has come under attack for selling objectionable content. In 2002, the US Justice Foundation, a conservative group, threatened to sue Amazon for selling Understanding Loved Boys And Boylovers. That title is still available through Amazon.
In 2009, Amazon stopped selling RapeLay, a first-person video game in which the protagonist stalks and then rapes a mother and her daughters, after it was widely condemned in the media and by various interest groups.
The author of The Pedophile's Guide, listed as Philip R Greaves II, still has other titles sold through Amazon.
AP