Because this seems like an appropriate topic/place to ask, are there say 20 books on a variety of topics that one can say are very useful to build a foundation of our world, in the physical and metaphorical sense? Literature probably shouldn't be in that list because literature is just a universe of its own and a lot of it is just not that accessible. E.g. I am not knowledgeable enough to be able to read Mahabharata or Odyssey in the original language.