Look into linear lights. You would run them around the inside perimeter of the bookcases like a rope light but the bulbs are open and accessible so you can change them as needed. They are spaced evenly on a track and use xenon bulbs. They're low volt so you'll need to plan for your transformer and lighting runs. Seagull is a manufacturer I have used in the past. Linear lights are also available as LED lights and they too use a transformer.
Linear lights are excellent for even, dim-able light.