On Wednesday, textbook authors David Knox and Caroline Schact sued Cengage over its forthcoming subscription service Cengage Unlimited. The plaintiffs claim that new business model for Cengage for the leading educational publisher is unfair.

“The authors claim that Cengage, ‘is systematically dismantling and frustrating’ sales of their works in favor of selling subscriptions to Cengage’s digital products,” Andrew Albanese, Publishers Weekly senior writer, explains. “This matters [for Knox and Schact] because instead of earning a contractual royalty based on each sale, the publisher is now seeking to pay authors a piece of the subscription revenue based on a formula the publisher alone has devised.”

The core claim, Albanese tells CCC’s Chris Kenneally, is that with “the pivot to a digital subscription service, Cengage has ‘wrongfully’ implemented ‘a unilateral change to the compensation structure for its authors,’ from ‘the contractual royalty-on-sale’ compensation model to a relative use’ model.”