The world's second-wealthiest country, Japan once seemed poised to overtake America as the leading global economic powerhouse. But the country failed to recover from the staggering economic collapse of the early 1990s. Today it confronts an array of disturbing social trends, notably a population of more than one million hikikomori : the young men who shut themselves in their rooms, withdrawing from society. There is also a growing numbers of "parasite...