California’s Age of Learning is partnering with Ohio-based children’s magazine publisher Highlights to add more content to the ReadingIQ digital library. Available now, the Highlights Reading Quest series features 100 books, each containing multiple stories focused on themes like summer camp or springtime.

The Reading Quest books include accompanying audio for pre-readers and are broken up into levels to help teachers and families match children with stories that are appropriate for their reading ability.

Earlier this year, Age of Learning snapped up the exclusive digital rights to National Geographic Kids’ latest Weird But True book with Weird But True! 10: 350 Outrageous Facts rolling out as part of the ReadingIQ digital library. Since its launch in 2004, Weird But True has been the most popular feature in National Geographic Kids’ magazine, covering a range of topics including space, weather, food and pop culture.

ReadingIQ targets under-12s and features more than 1,000 exclusive titles. The digital library launched in November and is available for teachers to use in classrooms at no cost, while families can subscribe for access to the library for a monthly or annual fee. The app is available through the App Store or Google Play.