[ElefantPhace][1] provided an answer for Music. Here's for [Books][2]: > You can access your books on different devices, including compatible > Android devices, iPads, iPhones and iPod touches, or on the web on > your computer. No matter where you read your books, when you're > connected to a network (via Wi-Fi or a data connection on your device) > we'll automatically keep track of your reading place, so you can pick > up right where you were last reading the next time you open your > ebooks > > Note: **In rare occasions when a user tries to access books on a number of devices at the same time, our system may temporarily block > them from opening new reading sessions.** This can happen when too > many readers are open on different machines or browsers. If your other > reading sessions are closed or inactive, you will be able to read in > this browser after a short delay. If you believe this is an error > please contact our support team. [1]: https://android.stackexchange.com/users/30793/elefantphace [2]: http://support.google.com/googleplay/bin/answer.py?hl=en&answer=179841