Editor's note.

When bad things happened--when there were wars, or grisly accidents, or, God forbid, terrorist attacks--my mother-in-law used to be fond of declaring, in a country woman's common-sense tone: "Everything would be fine if people just stayed in the house." We'd laugh and acknowledge the grain of irrefutable truth in her aphorism (a conversation-ender if there ever was one), and I'd keep my obvious retort--"Yes, but how small and dull and uninteresting such a risk-free world would seem! "--to myself. The idea my mother-in-law was disinclined to endorse--the ...