Unable to open Kindle app after update to 15.3.1 on iPad

Try force closing it: Link-> Quit and reopen an app on iPad - Apple Support

Also, your purchased books should be tied to your Amazon account, and should return once you sign in to your account on the app after you re-download it.

fayefromhome wrote:

The screen is frozen on the title page of a book. Afraid to delete app and re-install because I'd lose all my books/data. What to do?

If your iPad won't turn on or is frozen - Apple Support