The ten books (seven Harry Potter, three Hogwarts Library) became available via the all you can read ebook subscription service today. Unlike library ebooks subscription services provide access to all books in their collection at all times. In other words, never a wait.
From Oyster:
Make sure your Oyster app is updated to version 1.9 and ¾ (you can get it on the App Store and Google Play), and then open a Harry Potter title to get the full effect. Once inside, rather than one of Oyster’s reader themes, choose one of the new “House Themes”—with designs inspired by Gryffindor, Slytherin, Ravenclaw, and Hufflepuff—or tap the Sorting Hat icon to have one selected at random. Then dive into a custom reading experience inspired by your favorite Hogwarts House.
The Harry Potter experience continues throughout the app. On the new Harry Potter page in the Explore tab, discover more books Harry Potter fans will love on Oyster.
By the way, Oyster’s literary publication The Oyster Review (free access) will feature some original content celebrating Harry Potter for the remainder of the week.
Worth Mentioning
Harry Potter books are also part of the Amazon’s Kindle Unlimited service. They first became available as part of the Kindle Owners’ Lending Library in June 2012. However, as of today, the three Hogwarts Library Books are not available via Kindle Unlimited but are part of the Oyster service.