You can either: go to your library and you go to the book you want to delete, but don't click on it and in the top right hand corner there should be a little Red Cross, just click on that. Orrrrr you can click on the book as if you were reading it, and then click the button in the top right corner that says 'manage' and some kind of list thing should come up with boxes, and there's one that says 'my library' or something like that, with a box with a cross in it next to it, and then all you do is click on that box so it doesn't have a cross in it and that's it