Why do some people (e.g., Europeans) go on to build great civilizations while others (e.g., Native people in North and Central America) lag behind? In this celebrated book, Jared Diamond puts forward the proximate causes (indicated by the title) and the ultimate causes (https://en.wikipedia.org/wiki/Guns,_Germs,_and_Steel)
Several years later, he wrote a follow-up (https://en.wikipedia.org/wiki/Collapse:_How_Societies_Choose_to_Fail_or_Succeed) that attempted to explain why civilizations collapse. Using his theory, you can speculate the future of humanity as a whole. If you haven’t read it before, it is time to read it now. Since given recent developments, it is high time we wake up from the 25-year interlude during which we stopped worrying about the risk of imminent annihilation of humanity and ponder on its future.