"Of all the things humans rely on plants for--sustenance, beauty, fragrance, flavor, fiber--surely the most curious is our use of them is to change consciousness: to stimulate or calm, fiddle with or completely alter, the qualities of our mental experience. Michael Pollan dives deep into three plant drugs -- opium, caffeine, and mescaline -- and throws the fundamental strangeness, and arbitrariness, of our thinking about them into sharp relief. Exploring...