Amazon will not hand over information on how it searches and indexes the text of books, filing an objection in U.S. District Court in Seattle. Google had subpoenaed the online retailer in its fight against the Authors Guild, which sued the search engine in September of last year.

The information that Google requested was "highly confidential," Amazon said, and would require the divulging of trade secrets. Instead, the company directed Google to publicly available information on the Web about its book search methods.

Still outstanding are two subpoenas, one to Microsoft and the other directed at Yahoo. Neither company has responded to the requests as of Wednesday.

The rejection by Amazon is a blow to Google's case, as its data could have proven valuable in defending its book controversial search project.

Google has struck out on its own, following an "opt-out" system where it is the responsibility of publishers to ask the Mountain View, Calif. company to not index their books. Contrast this with Amazon and Microsoft, whose offerings have an "opt-in" system.