As the Federal Trade Commission moves towards what looks like a lawsuit against Amazon, several authors, booksellers, and anti trust activists want Amazon’s bookselling to also be investigated.

The Authors Guild, the American Booksellers Association, and antitrust think tank Open Markets Institute sent a letter Wednesday to the Justice Department and the Federal Trade Commission requesting that they disrupt the monopoly on the book market that Amazon has.

The retail giant’s influence on the book world can’t be overstated — 40% of physical books sold in the U.S. are sold by Amazon, as are 80% of e-books sold. Amazon’s 2008 purchase of Audible has also helped it dominate the realm of audiobooks. The reason this is an issue for the world of publishing is that, for one, it has resulted in fewer books sold by physical bookstores across the country. And Amazon has a tendency to highlight well-known authors, making it even harder for other, lesser-known authors to get attention on their books.