This chapter raises the following main points:• Regions are groupings of states that share either geographic proximity or have sufficient cultural/historic ties that bind them together.• Regionalization occurs within a region as interdependence is developed among the regional states.• The development of regionalism is dependent on the support of the regional great power(s), the extent of reciprocity that exists in the relations of the states in the region, and the level of strategic reassurance that exists among these states.• Regionalization is not a lineal process, that is, it can increase or decrease.• The pace of regionalism is different in each region but a basic pattern exists where economic integration preced...