In an email alert to members, sent on Friday, the Guild argued the tool could eat into sales of certain types of books, including cookbooks and reference texts, and advised that some authors might do well to have their books removed from the service. Controversially, the group argues that publishers' contracts don't entitle them to take part in the service without the author's permission.
The service, dubbed "Search inside the book", lets users type in any keyword and receive results for all the pages and titles of various books that contain that term. In the past, Amazon customers could search only by author name, title or keyword. The search feature works with around 120,000 titles from 190 publishers, which translates into some 33 million pages of searchable text.
The service, launched as a partnership with the publishers that are displaying the titles, has been combined with the site's standard search.
The Guild said that while the tool could benefit older titles and those that don't receive a great deal of attention, the value of other books would be eroded. "Most reference books would be at clear risk in such a database," the Guild advised. "So would many (if not most) travel books and cookbooks."
Part of the problem is that the search tool doesn't place strict enough limits upon what users can see, the organisation said. "It turns out that it's quite simple (though a bit inconvenient) to look at 100 or more consecutive pages from a single lengthy book," the group said. "So a reader could choose to print out all the fish recipes from a cookbook in the programme. Or the section on Tuscany from a travel book."
Determined college students could print hundreds of pages from textbooks, the Guild warned.
Publishers need an author's consent to place a book on the service, the Guild argued, although the publishers don't agree. "Most argued with our interpretation of their contract (no surprise there), but some have said that they would remove a work from the programme if the author insisted," the Guild said.
CNET News.com's Dinesh C. Sharma contributed to this report.