Listen to ebooks and music at the same time!

Shuttle music player (use the equalizer feature to reduce the music volume while playing back an ebook):
play.google.com/store/apps/details?id=another.music.player

My video explaining how to get your phone to read books aloud:
geoffmobile.com/blog/make-your-phone-read-a-book-aloud-to-you-text-to-speech-for-ebooks-on-android