Toward
the end of the last ice age, some 15,000 to 20,000 years ago, a few of
the human communities that were most favoured by geography and climate
began to make the transition from the long period of Paleolithic, or Old
Stone Age, savagery to a more settled way of life depending on animal
husbandry and agriculture. This period of transition, the Neolithic
Period, or New Stone Age, led eventually to a marked rise in population,
to a growth in the size of communities, and to the beginnings of town
life. It is sometimes referred to as the Neolithic Revolution because
the speed of technological innovation increased so greatly and the
social and political organization of human groups underwent a
corresponding increase in complexity.