Reading at night, particularly with a partner, can be problematic thanks to the required light source. But the Super Slim LED Page Light might help. The thin unit is placed on the current page, and four white LEDs shine into the clear cover and out onto the page, making a uniform light source without shining a light in your eyes.
The page light is powered by 4 AAA batteries, and it will last for about 40 hours on a set. There is a light adjustable switch, and the unit weighs about 210g. The overall measurements are 235*180*15mm (9.25x7x.6 inches).
The Super Slim LED Page Light sells for $25, and it can be found at Gadget4All. The only problem I see is that my books tend to vary a lot in size, so it may not work as well for some as it does others.