A device for illuminating a generally flat surface essentially without emitting significant light beyond the surface is particularly adapted for use as a book light. The device comprises a battery-operated light source contained within a housing to which a transparent light-conductive illuminating body is mounted in close adjacency to the light source to transmit the light through the illuminating body. The device may be placed with the illuminating body over a book or other flat surface for illuminated viewing through the transparent illuminating body. The illuminating body is tapered in a wedge shape to deflect the conducted light onto the underlying surface.