After seeing that a movie adaptation was in production, last week I downloaded Suzanne Collins' novel The Hunger Games—and I didn't pay a thing for it. But I didn't turn to piracy. Instead I visited Amazon.com, where the company's new "Kindle lending library" offers those with Kindle hardware and an Amazon Prime subscription one free book to read each month. It's a terrific new benefit for Prime users, and it's clearly designed to hook people on Amazon hardware (like the new Fire tablet) and digital content.

Amazon attracts more customers to e-books, readers get free content, and publishers get paid. Everyone's happy, right?

Wrong. The Authors Guild, which represents the interests of writers, blasted the program yesterday, saying that the lending library program is built on "nonsense" and a "tortured reading" of Amazon's contracts with publishers.

"Amazon, in other words, appears to be boldly breaching its contracts with these publishers," wrote the Guild. "This is an exercise of brute economic power."

According to the Guild, Amazon was unable to secure lending library deals from most major publishers, so it simply went ahead with the program. Instead of having a specific arrangement in place with publishers, Amazon just pays publishers the wholesale price each time a Prime member downloads a book from the lending library; in other words, Amazon treats each download like a sale and pays accordingly.

But the Guild argues that Amazon isn't really "selling" these books, but instead creating a new program with them for which it lacks any permission from publishers. Yes, publishers are getting paid, but they also want some level of control over how their works are used—and having Amazon unilaterally run a "lending" program where books cost end users nothing might not be appealing to some publishers who want to avoid even further price erosion in the e-book market.

"From our understanding of Amazon’s standard contractual terms, this is nonsense—publishers did not surrender this level of control to the retailer," says the Guild. "Amazon’s boilerplate terms specifically contemplate the sale of e-books, not giveaways, subscriptions, or lending (Amazon does have a lending program that some publishers have authorized, but it’s a program that allows customers—not Amazon—to lend their purchased e-books). Amazon can make other uses of e-books only with the publishers’ consent."

Publishers have long been at odds with Amazon, even though they've been paid for their books. For instance, Amazon used to run its e-books operation like a traditional retailer might; it paid the wholesale price for each book sold, but was free to set its own price however it liked. Amazon for a while tried to establish $9.99 as the standard e-book price, even when this meant selling at a loss. Publishers balked and used the appearance of the iPad (and Apple's own e-book store) to pressure Amazon into an "agency model" where the retailer simply takes a percentage of whatever price the seller picks. The idea was to prevent the book business from ceding too much power to a single retailer, as happened with iTunes and music.

Publishers and authors want more than a simple payment when a book is used; they want some say over those uses. The Kindle lending library looks like the newest battleground in a long war.