WASHINGTON (AP) — The biggest U.S. book publisher’s plan to buy the fourth-largest for $2.2 billion represents a key test for the Biden administration’s antitrust policy. So much so that the Justice Department is calling an out-of-the-ordinary witness to The Stand: author extraordinaire Stephen King. Penguin Random House’s proposed acquisition of rival Simon & Schuster would reduce the “Big Five” U.S. publishers to four. The Justice Department has sued to block the merger, contending it would thwart competition, and hurt authors and readers. The publishers are fighting the lawsuit. The trial is set to open Monday in federal court in Washington, D.C.