Japanese maps tend to come in two varieties: small, schematic, and bewildering; and large, fantastically detailed, and bewildering.

Historically, large-scale global trade has served two functions: 1) the exchange of goods between willing sellers and buyers described in Econ 101 textbooks; 2) as a tool of state aggrandizement, in which the private parties are stand-ins for governmental interests.

Major power and telephone grids have long been controlled by computer networks, but now similar systems are embedded in such mundane objects as electric meters, alarm clocks, home refrigerators and thermostats, video cameras, bathroom scales, and Christmas-tree lights - all of which are, or soon will be, accessible remotely.

Scientists have established huge numbers of links between particular diseases and snippets of DNA, but in the great majority of cases, this has not yet been translated into treatments that can help cure patients. These treatments will come - tomorrow, or the day after.

Compared with U.S. cities, Japanese cities bend over backward to help foreigners. The countryside is another matter.

In 1491 the Inka ruled the greatest empire on earth. Bigger than Ming Dynasty China, bigger than Ivan the Great’s expanding Russia, bigger than Songhay in the Sahel or powerful Great Zimbabwe in the West Africa tablelands, bigger than the cresting Ottoman Empire, bigger than the Triple Alliance (as the Aztec empire is more precisely known), bigger by far than any European state, the Inka dominion extended over a staggering thirty-two degrees of latitude—as if a single power held sway from St. Petersburg to Cairo.

A world with a sudden limit on air travel would be tremendously different from the one we live in now.