O.K..I asked this questiona as a newbie.. I bought a KOBO for my wife..she loves the thing ..but now after a few days she / we can't figure out how to toggle the screen from white background to black background. This should be a simple push of a button. Why would it not be included under Display... where you change the font size.. Just this simple frustration for me could turn the thing into a rectangular flat frisbee.. Anyway if someone knows the simple answer I would really like to know.