Nevertheless, Google is promoting its e-book plan as a fundamentally different and more “open” alternative to its rivals’ stores. Though it will act as a retailer and sell books from its own site, it will also behave like a wholesaler and allow independent bookstores and other partners to sell its e-books on their own sites.

People who buy Google e-books will not be locked into any particular reading devices or book formats, the company said. Books bought from Apple’s iBookstore, by contrast, can be read only on Apple devices.

“I don’t think anyone who has bought an e-reader in the last several years has really intended to only buy their digital books from one provider for life,” said Tom Turvey, Google’s director of strategic partnerships, who heads the Google Editions project.

Mr. Turvey said that customers would be able to get access their books, or buy new ones, from anywhere in the world by entering their Google credentials. And he said Google would introduce the service with a broad selection of hundreds of thousands of books, including trade fiction, nonfiction and professional, scholarly and academic titles, including textbooks.

Google already has two million books that publishers have made available as part of its Partner Program, which allows Web users to sample lengthy previews of books on Google’s site and other sites. A separate project to scan millions of out of print or hard-to-find library books has been tied up in litigation since 2005.

As a wholesaler, Google will play a role similar to that of offline distributors like Ingram Book and Baker & Taylor, which buy books from publishers and resell them to bookstores. Those companies generally keep a single-digit percentage of each sale, and Mr. Turvey said Google would operate along similar lines.

Independent bookstores seem to believe that Google is more interested in working through them than being a direct retailer. In fact, they are banking on it.