Two wonderful posts by Brad DeLong, (here  and here ) on the economic changes of the last century. One highlight (there are many) is his list of what a professor in the distant future would want students to know about the world economy at the start of the twentieth
At most, seven things:
First, that the world at the start of the twentieth century–even the
most advanced economies at the start of the twentieth century–were
very, very poor relative to how they would be at the century’s end. But
that was about to change.
Second, that the spread of ploughs that pulled themselves and looms
that wove by themselves was about to end the pre-industrial era, and
promise to make the world amazingly rich by all previous standards.
Third, that the ten thousand years in which people had lived largely
in small groups in villages was about to end: people were starting to
live in large groups in cities.
Fourth, that in the late nineteenth century transportation costs had
finally fallen low enough and transport speeds had become high enough
to make mass intercontinental shipment of goods and people possible: a
global economy and, because of telegraph and all the rest, a global
polity too. This fall in transportation costs had for the first time
created the possibility of a global economy–an economy in which
movements of people and goods across oceans and between continents were
central to how the economy worked, rather than mere precious and luxury
froth on the surface of a deep ocean.
Fifth, that this global economy was on its way to becoming a global
market. The era in which goods were either consumed at home, consumed
by you relatives, traded among your neighbors, or offered up to keep
the thugs with spears or the thugs with quills from killing you was
also coming to an end. Supply and demand would rule–which does not
mean that thugs would not use force to manipulate supply and demand.
Sixth, that the fall in transport costs and rise in transport speeds
had come about when the military-force gap between the North Atlantic
and the rest of the world was at its maximum–which meant imperialism,
formal or informal, and colonialism, open or masked.
Seventh, that the people were standing up politically. In proportion
as populations became urbanized and as rural populations became
commercialzed and plugged into the global communications network,
politics became democratized: rulers found themselves depending in fact
as well as in noble flights of fancy on the consent of the governed–a
consent that could be extracted for a while at gunpoint or