The New Yorker has published an article about Google Book Search by Jeffrey Toobin in its February 5, 2007 issue ("Google’s Moon Shot: The Quest for the Universal Library").
Here’s a quote from the article:
Google asserts that its use of the copyrighted books is "transformative," that its database turns a book into essentially a new product. "A key part of the line between what’s fair use and what’s not is transformation," Drummond said. "Yes, we’re making a copy when we digitize. But surely the ability to find something because a term appears in a book is not the same thing as reading the book. That’s why Google Books is a different product from the book itself." In other words, Google says that being able to search books on its site—which it describes as the equivalent of a giant library card catalogue—is not the same as making the books themselves available. But the publishers cite another factor in fair-use analysis: the amount of the copyrighted work that is used in the creation of the new one. Google is copying entire books, which doesn’t sound "fair" to the plaintiff publishers and authors.