When the largest publisher in the U.S., Penguin Random House, struck a deal in the fall of 2020 to acquire its rival Simon & Schuster, publishing executives and antitrust experts predicted that the merger would draw intense scrutiny from government regulators. The merger would dramatically alter the literary landscape, shrinking the number of major publishing houses — known in the industry as the Big Five — to four. (Or, as one industry analyst put it, it could create the Big One and the other three.) Last fall, the Biden administration sued to block the $2.18 billion sale as part of its new and more aggressive stance against corporate consolidation. The trial began on Monday, with oral arguments at the United States District Court for the District of Columbia. Tap the link in our bio to read our explainer of what we know about the case and its implications for the book business. 📸: @hiroko.masuike /The New York Times