I would obviously list Tolkien and the Dune series as required reading material, but I am sure others can add more, especially the philosophical works that influenced RSB (obviously Nietzsche, by his own admission) or books that explore similar themes?
Hegel and Heidegger, but I can't *recommend* them--life is short!
Hegel--Phenomenology of Spirit--vast movements of spirit across history
Heidegger--Being and Time--questioning traditional answers to the problem of being a being, proposing new/extra-old stuff
