Earlier this week vigilant browsers of Amazon.com were treated to a preview of its new e-book subscription service, Kindle Unlimited. The page, which was quickly taken down, announced that the service would offer “unlimited access to over 600,000 titles . . . for just $9.99 a month.”

Now it’s official. An Amazon press release confirms the numbers above, and announces some high profile offerings in its catalogue.

Subscription services, which allow readers to pay a monthly fee for unlimited access to all the e-books in the service’s catalogue, have been on the rise in recent months. The two leading firms in the subscription market—for now—are Oyster and Scribd, who both released statements welcoming the competition, according to a report by Digital Book World.

Among the most pressing questions raised by this fledgling distribution model is: How will authors and publishers be compensated? In a thorough article on the topic, Publishers Lunch breaks down what is known so far. Amazon will have direct subscription contracts with some publishers, who will receive credit for a “sale” of any given title once a reader has browsed more than 10% of it—a number that Amazon is free to change at any time. But it appears that, as with the Kindle Owners Lending Library, Amazon will take the position that it may offer a publisher’s titles without direct consent, so long as it pays the publisher the normal price of the e-book as soon as a reader opens it. Amazon has not specified which publishers’ books are offered under which model.

Additionally, Amazon will automatically enlist the 500,000 or more self-published books in the Kindle Direct Publishing Select program in its new subscription service. Authors enrolled in KDP Select can earn a higher royalty percentage from Amazon in exchange for making their books exclusive to the Kindle store. For now at least, Amazon won’t enroll self-published authors in Kindle Unlimited unless they are members of KDP Select. These authors are then compensated for their “sales” via a pro-rated share of the monthly KDP Select cash pool, the size of which is determined by Amazon, which raised the July pool from $1.2 to $2 million in anticipation of a spike in readership prompted by the Kindle Unlimited rollout.