Food of the Gods says psilocybin mushrooms were responsible for the unusually fast evolutionary growth of the human brain. Also it talks about how our relationships to psychoactive plants (including caffeine, sugar and alcohol) shaped human cultures. Finally, how we may restore personal, social and ecological balance in the world.
The Four Agreements isn't new age nonsense. It explains how language creates our "dream" of reality (an idea from modern linguistics.) It also shows how you can live a better dream by not taking anything personally, not judging yourself and always doing your best.