This introduction traces the origins of agriculture and the character of early agricultural communities across the world and surveys the development of the more complex social structures and cultural forms that agriculture enabled. Like modern scientists, however, some experimenters either unwittingly or intentionally manipulated the genetic make-up of plant and animal populations, selecting for traits and characteristics that were more productive or more pleasing and thus preferred. Food production has been linked to significant changes in landscapes and populations that eventually supported the rise of urbanism and enabled human populations to expand from 6 million to over 7 billion today. Alan Outram describes how, whether keeping a few livestock within a mixed farming system or maintaining large herds and flocks in systems of specialized pastoralism, the key limiting factors that have to be solved are access to grazing land and, for times of the year when the natural grazing is insufficient, adequate supplies of fodder.