When I saw this picture, I thought there must be some kind of really clever thing going on, or a custom made flat LED strip, or a… no. It’s a tiny CFL lamp stuck in a book which has had many of its pages cut out. I was kind of hoping for more, but to be honest, simple can be good sometimes as well. Full instructions here.
Bonus points for using light-related book titles — Illuminatus Trilogy, The Light That Failed, The Sun Also Rises, etc.