https://consumerist.com/2017/08/08/amazon-tells-third-party-booksellers-to-speed-up-deliveries/

That paperback book you ordered from Amazon for your upcoming beach vacation might just arrive faster than you thought. But it’ll come at a new cost for the third-party seller providing the title: Amazon is once again tightening the reins on sellers who don’t use the company’s fulfillment services, reducing their required delivery window.

Just days after Amazon changed the way returns work for third-party merchants — bringing the experience more in line with Prime services — CNBC reports the e-commerce giant is making a similar change to the way the sellers who fulfill their own book, CD, and DVD orders deliver the goods.