Physical health is relatively easy to measure. We can time how fast one can run 100 meters, or measure the maximum weight a person can lift. To measure mental health is not that easy and the lack of mental health is not obvious either. But good mental health is as important as or even more important than, physical health, for our well-being. Book catalogues have many books on how to increase physical fitness, but few on improving mental health. I have practised psychiatry for over two decades and seen most of the mental illnesses described in textbooks. I have talked to many people who,...