The Kindle app is available for most major smartphones, tablets and computers. That means with this free Kindle reading apps, one can buy a Kindle book once, and read it on any device with the Kindle app installed. One can also read that same Kindle book on a Kindle device if he own one. With Amazons Whispersync technology, one can automatically save and sync his furthest page read, bookmarks, notes, and highlights across all the devices. That means one can start reading a book on one device, and pick up where he left off on another device.