A really good book has a sense of permanence and speciality to it that outlasts typical online content. Philosophy and mathematics books, for example, tend to

A really good book has a sense of permanence and speciality to it that outlasts typical online content. Philosophy and mathematics books, for example, tend to exist outside time because they are dealing with fundamental unanswerables and constructions of assumption, not "extent of our knowledge" empirical observations as with science. If their thinking is robust, they never go out of date. History books likewise indulge in rich storytelling about what happened and why. The story is assembled with fact, but filtered through the historiographical lens of the author. There are many niches of history that can only be studied in books. History is easily revised, but each telling can uncover a more "complete" truth. And fiction, of course, captures the world as a non-factual experience and therefore says the things that can't be said(no words for them, little concept or attention given to them). As a storytelling medium, writing is not everyone's preference, but it is the singular most productive form we have, and so a lot of fiction books express forgotten corners and small whispers of thought. Given that you have a serious temperament I would recommend starting with very old books from ancient times, since those are the ones least likely to be "obsolete" - power laws being what they are.