Why is my deleted book still showing on my Kindle?

Deleting the book from Amazon's page doesn't delete it from your Kindle. Instead, on the Kindle itself, go to the Home page where you get the list of books on your Kindle. Using the little square box to the right of the A-Z keys, move down the list until you're on the book you wish to delete. Then use the right hand surrounding bit of the square (which should have a tiny right hand arrow on it), and press that little arrow. You will get a picture of the book and a list of options. At the bottom, click on 'Remove from device,' and it will delete it.