Google has updated its Google Books app for iOS and Android to include the ability to side load ebooks to your device. Traditionally, Google has allowed only books purchased on Google Play or found within public domain to be read within the Books app, but that's now changed.
You can now upload up to 1,000 of your own books to Google Books, in either EPUB or PDF formats - both of which are pretty standard. Books can be uploaded through the Google Books web interface, or even more conveniently, through Google Drive if under 50MB. Google will make your uploaded book just like one that was purchased, syncing data across iOS, Android, and web including what page, bookmarks, and any notes that a reader may take.
Furthermore, Google has included a redesign within the Google Books app for Android. You'll now notice a refreshed design for the library, Table Of Contents view and the recommendation page at the end of books. Additionally, stability and performance improvements have been included, and a confirmation dialog to prevent you from accidentally un-downloading a book.
Are you a big book reader? Grab the update from the respective stores.