Thanks, kiwidude! Unfortunately I had just added my new batch of books (having noted them on paper) prior to seeing your post. But I've downloaded your plugin, installed it, and set options as per your instructions, so I'm primed and ready for my next batch.
I love that you created an image for the button, rather than leaving it blank, as with some other plugins, and that you've made the options readily available. Well done! Can't wait to use it.