Penguin Random House, the biggest book publisher in the U.S., is in the process of buying Simon & Schuster , a deal that would create a megapublisher responsible for roughly one-third of published books. But the deal requires approval from the Biden administration — and some authors’ groups and other organizations are calling on the Justice Department to block it, as a violation of antitrust laws.

Critics say the merger would create multiple problems, as our colleague Elizabeth Harris writes . Many authors could receive less money, because fewer publishers would exist to bid on their proposals. Writers without a proven track record might struggle to be published at all, and the industry could become even more dependent on blockbuster titles.

“There are projects that would have sold for $150,000 years ago that might not sell at all now to the big five, whereas the book that would have sold for $500,000 might go for a million,” one literary agent told The Times .

Still, many people in publishing consider Amazon the biggest threat to the health of the book business. “If it’s correct to worry about a merged company that publishes perhaps 33 percent of new books,” Franklin Foer wrote in The Atlantic, “then surely it’s correct to worry more about the fact that Amazon now sells 49 percent of them.”