Major book publisher Macmillan is warming up to the growing world of book subscriptions, announcing today that it will provide hundreds of its most popular book titles to unlimited e-book subscription services Scribd and Oyster.

The move should make these “all-you-can-eat” e-book services much more attractive to voracious readers, especially those who like the idea of having an entire public library’s fiction section in their pockets at all times. Macmillan is the fifth largest book publisher in the world, and owns licensing rights to titles from known sci-fi authors like Ursula K. LeGuin, Elizabeth Bear, and Orson Scott Card, to name a few. Until now, you weren’t able to access Macmillan book titles from either Scribd and Oyster — both of which offer comparably-priced ebook services for $9 and $10 per month, respectively.

The move also means both Scribd and Oyster could be more attractive to avid digital book readers than the rival service from online book retail giant Amazon, which offers its Kindle Unlimited service for $10 a month, minus many of the more popular book titles.

And so begin the ebook subscription wars of 2015 — one of 9 media trends to watch in 2015.