The government’s decision to pursue major publishers on antitrust charges has put the Internet retailer Amazon in a powerful position: the nation’s largest bookseller may now get to decide how much an e-book will cost, and the book world is quaking over the potential consequences.

As soon as the Department of Justice announced Wednesday that it was suing five major publishers and Apple on price-fixing charges, and simultaneously settling with three of them, Amazon announced plans to push down prices on e-books. The price of some major titles could fall to $9.99 or less from $14.99, saving voracious readers a bundle.

But publishers and booksellers argue that any victory for consumers will be short-lived, and that the ultimate effect of the antitrust suit will be to exchange a perceived monopoly for a real one. Amazon, already the dominant force in the industry, will hold all the cards.

“Amazon must be unbelievably happy today,” said Michael Norris, a book publishing analyst with Simba Information. “Had they been puppeteering this whole play, it could not have worked out better for them.”