The most important technological development ever to occur in human history was the domestication of plants (agriculture) and animals (pastoralism). Together these developments are called the Neolithic Revolution and they allowed the development of urban centers (towns and, later, cities), trade and most of the other things we consider to be components of "civilization." When and how did this most important event occur?
The Neolithic Revolution occurred first in the so-called "Fertile Crescent" or Mesopotamia in what is now modern Iraq. It also occurred independently (probably) at later dates in China, the Americas and possibly in parts of Africa and New Guinea. Agriculture and pastoralism diffused from Mesopotamia to Egypt, Western Europe and the Indus Valley (modern Pakistan).
To understand how the Neolithic Revolution occurred it is necessary to understand the economic system it replaced. Until the Neolithic, and in most areas for a long time after, all humans engaged in an economic activity called "hunting and gathering" which is exactly what it sounds like—the acquiring of food by hunting wild animals and gathering wild plants. This system is called "food extraction" as opposed to "food production" by agriculture and pastoralism. Hunting and gathering is actually a very efficient system that much of the time produces ample food. The main disadvantages are an inability to maintain surpluses against bad times or for supplying non-food producers (craftsmen, leaders, etc) and the fact that it can only maintain (in most areas) a very low population density.
By comparison, agriculture and pastoralism, even in fairly primitive forms, provide large surpluses and can supply a much larger population per square mile. This allows a growth in population, an ability to store food against bad times and the maintenance of non-food producers who can specialize as craftsmen, warriors and leaders. These developments, in turn, allow...