International labour migration has played a significant part in economic development in nearly all advanced industrial countries since 1945.1 In recent years, it has also been significant in processes of industrialisation in the oil states and the so-called "newly industrialised countries" (NICS). Temporary international labour migration has been important in many areas. It takes several forms, and is not always clearly distinguishable from permanent migration (particularly in the long term). The following list summarises the main types of migration. Note that not all types are intended as labour migration, though all have a labour market and economic impact.