Just click on the Cover image and then browse with the arrows on your keyboard.
You can zoom in to screen-width and full size by clicking on the image once or twice.
It also remembers your zoom-state, which is pretty neat.
I originally wanted to make a PDF (or flash or other sort) e-book, but I needed you to be able to alternately see both pages side-by-side, as well as zoom-in on 1 page so you can properly read the text...
So, please tell me if you like this way of viewing my artbook, or if I should do it some other way.