It’s a small world after all. And if we don’t speak up, it will become smaller.

Penguin Random House, already the largest trade publisher in the country, has announced plans to buy Simon & Schuster from ViacomCBS for about $2 billion. If the deal goes through, the Big Five publishers will become the Big Four — or, really, an industry version of the Big Bad Wolf and the Three Little Pigs. . . .

As the number of publishers shrinks, authors find themselves with fewer potential buyers for their proposals and manuscripts. Bookstores are beholden to a smaller number of distributors. And readers face a shelf of titles further dominated by familiar bestsellers most likely to earn big payouts for massive corporations.

Penguin Random House. . .is already too big. The publishing house, which is part of the German conglomerate Bertelsmann, contains 320 imprints that release about 15,000 titles a year. Simon & Schuster publishes 2,000 titles a year.

In a statement released Wednesday, Penguin Random House chief executive Markus Dohle wrote, “We can successfully unite company cultures and prestigious publishing teams while preserving each imprint’s identity and independence. Simon & Schuster aligns completely with the creative and entrepreneurial culture that we nurture by providing editorial autonomy to our publishers.”

United but somehow independent, autonomous but also completely aligned — these are Orwellian reassurances. . . .Dohle’s statement is not really a description of corporate culture; it’s a preemptive defense against antitrust concerns.

In his own happy statement about the proposed merger, Simon & Schuster CEO Jonathan Karp suggests that the union was essentially fated in the stars. “From our company’s inception,” he writes, “there has been much cross-pollination between Simon & Schuster and Penguin Random House. In fact, the founder of Random House, Bennett Cerf, met Max Schuster when they were both students at Columbia Journalism School.”. . .

A vibrant democracy needs more editorial diversity representing a broader range of tastes and interests. Bertelsmann’s omnivorous strategy is particularly alarming because Simon & Schuster plays a unique role in the United States as a leading publisher of high-risk political books, such as John Bolton’s “The Room Where It Happened” and Mary Trump’s “Too Much and Never Enough” — both of which President Trump tried to squelch through lawsuits and public intimidation.

Merging such a publisher into an even larger corporation would further diminish competition and make such risk-taking less attractive. . . .In the future that Bertelsmann celebrates, we can all read anything we want so long as it’s a bestseller by John Grisham. . . .

Sally Hubbard, Lynn’s colleague and the author of a new book called “Monopolies Suck!” (published by Simon & Schuster), sees a host of problems already arising from the unfettered power of publishing conglomerates, news corporations and social media platforms. “Diversity of speech and a marketplace of ideas are incredibly important,” she said. “We’re seeing this across the whole economy, whether it’s online speech and the consolidation of the control of speech with Facebook and Google or whether it’s the destruction of local news and journalism. You start having a less pluralistic society, more concentration of ideas through fewer gatekeepers.”

Hubbard said margins already are so squeezed that publishers do not have as much money “to take risks on new authors who don’t have followings.” Projects that take years of research fall by the wayside. But, of course, the damage to our culture is hard to notice. It’s a shelf of books not published.

Hubbard and Lynn agree that the root problem is the swelling power of Amazon. (Amazon CEO Jeff Bezos owns The Washington Post.) They say the Justice Department’s fixation on low prices has allowed Amazon to become a dominant buyer and retailer of publishers’ books. The online giant is now so large that it can impose increasingly challenging terms on publishers. “That’s an extortive and extortionary relationship,” Hubbard says, “not a healthy marketplace.” Publishers have responded in exactly the way we’re seeing this week: further consolidation.

Hubbard said the situation is so extreme that the Justice Department should allow publishers to engage in collective bargaining with Amazon. That could help protect publishers’ margins and ensure at least a little variety among our creative gatekeepers.

But unless there’s a radical attitude adjustment in Washington, that’s not likely to happen. On Wednesday, Dohle told Publishers Weekly that he does not expect any antitrust issues to arise, which is a shameful comment on the attentiveness of the country’s antitrust regulators.

Anybody who cares about the biodiversity of our intellectual and creative culture should speak up now. The future of American literature could soon be a forest of lovely trees — all oaks, neatly trimmed.

Ron Charles writes about books for The Washington Post and hosts