The Authors Guild, along with five other writers’ groups and the nonprofit Open Markets Institute, has sent a letter to the Department of Justice asking the government to block Penguin Random House’s pending acquisition of Simon & Schuster. In asking for the DoJ to step in, the organizations framed the proposed acquisition as part of the ongoing consolidation within the entire publishing industry—including in the bookselling field, which is now dominated by Amazon—that the letter writers say has gone too far.

“The time has also come to recognize that simply blocking takeovers is no longer sufficient,” the letter states. “The Department of Justice must begin today to proactively restructure the entire U.S market for books in ways that also deal with the danger posed by Amazon.”