In a letter to merchants who sell used books online through Amazon, CEO Jeff Bezos defended the company's policy, saying that "Amazon.com is now, and has always been, supportive of and good for authors."
In the letter, a copy of which was posted to a Usenet discussion group, Bezos asks booksellers to write to the Author's Guild "explaining how the sale of used books actually helps the entire book industry."
The Authors Guild, the largest organization representing published authors, asked its members earlier this month to to Amazon from their Web sites.
The Guild has already received about 4,000 e-mails in favor of Amazon, said Kay Murray, general counsel. Amazon spokesman Bill Curry said Bezos sent the letter to "tens of thousands" of sellers of used books Sunday night.
The Guild argues that Amazon's policy of listing used copies next to new versions of the same book for sale "does damage to the publishing industry and decreasing royalty payments to authors and profits to publishers."
But in his letter, Bezos countered that offering the used books encourages customers to visit the site more frequently and buy more books. And buying some books at a cheaper price "gives them a budget to buy more new books."
In an argument familiar to those who have followed the debate over online music, Bezos pointed out that those who buy a book "are also buying the right to resell that book, to loan it out, or to even give it away if they want."
While he encouraged the used booksellers to be "polite and civil" in their letters to the Guild, he did take a few swipes at it himself, saying that this "is the same organization that from time to time has advocated charging public libraries royalties on books they loan out."
A statement on the Authors Guild site says the Guild advocated 15 years ago for a government-funded royalty paid to authors of books borrowed from libraries.
Murray called Bezos' arguments regarding used-book sales "disingenuous," saying, "All we've done is tell our members that it's not in their economic interests to link to Amazon."
"We do not oppose used-book sales. And we did not ever take that position," Murray said. "What we oppose is the aggressive marketing of used copies of new titles. It's very clear if you go on the Amazon Web site and punch in a title or author you're going to be urged to buy the book used."