The idea here is to cut a route for your cable and get it at an angle so the light illuminates slightly forward (to maximize its backlighting). After that, you use the rubber band to hold the light bulb apparatus in place.
Obviously, you'd probably want to do this with a book you don't like as much, but has a decent weight so that it doesn't tip over and shatter the bulb. Speaking of lightbulbs, while the 7 watt CFL bulb from the IKEA lamp may be considered safe "enough" for most folks, we'd personally opt for a cold LED bulb so your awesome book lamp doesn't become a home disaster waiting to happen. And of course, there's the option to just use a more traditional beside lighting solution and preserve those pages.