If you have downloaded Kindle books on your Android device, they will be stored in the internal storage of your device. Specifically, Kindle books are saved in the "Kindle" folder within the "Books" directory. You can access this folder using a file manager app on your device. Alternatively, you can also view your downloaded Kindle books within the Kindle app itself by tapping on the "Library" tab and selecting "Downloaded" from the drop-down menu.