Immigration legislation is a debated subject among the attentive public and political operatives, at both the national and sub-national level of government, in the United States. In recent years, the American government has been more likely to pass new laws, with many states issuing new punitive measures intended to discourage migration into the US from Latin America. The move by sub-governments breaks with an historical pattern whereby immigration policy directives were the purview of the national government. American state governments, arguably, have been stirred to act because of gridlock at the national level. This book attempts to help better understand major immigration policy change at the national level in the US over the past 60 years, as a way to enlighten the contemporary debate. This book also discusses the political influences, challenges and economic impact immigration policies have in several other countries such as Italy, China and New Zealand.