It is perhaps significant to man that in terms of simple magnitude he is the mean between macrocosm and microcosm. Stated crudely this means that a super-giant red star (the largest material body in the universe) is just as much bigger than man as an electron (one of the tiniest of physical entities) is smaller. It is not surprising, therefore, that the prime mysteries of nature dwell in those realms farthest removed from sense-imprisoned man.