Ebooks are genius!
Read books on your vacation without taking up more space than the phone or tablet you were already packing. Continue reading on one device where you left off on another device. Choose your print size, screen brightness, and page orientation. Awesome.
But what about sharing an ebook with your spouse? Not so easy.
Or is it?
If you purchase an ebook from the Apple Store or the Google Play Store, the book is owned by the account the device is registered to — your Apple ID or Google Account. If you and your spouse do not share the account, you cannot share the books. For your spouse to read the same book without also buying it, he/she would need to read it on your device, or sign out of his/her account and sign into yours (this has many downsides and limitations; it is not at all practical).
However, if you purchase ebooks from Amazon (for the Kindle or Kindle app) or Barnes and Noble (for the Nook or Nook app), you can register your separate mobile devices to the same Kindle or Nook account — without impacting other phone functions — and share the books in different devices without re-buying them. And you can delete a downloaded book from one device without deleting it from other device(s).