United States Visas are used by over 171 millions of foreign nationals visiting the United States in 2007. Other foreign nationals come to live in the U.S. permanently. A foreign national wishing to enter the U.S. must obtain a visa If he or she is not a citizen of one of the twenty-seven Waiver Program countries.If he or she is not a citizen of Canada or Bermuda.

There are two basic types of U.S. visas, Non immigrant visa - for temporary visits such as for tourism, business, work or studying. Immigrant visa - for people wanting to be permanent residents in the United States without any time limitation. The Visa Waiver Program (VWP) is a program of the United States of America which allows citizens of specific countries to travel to the US for tourism or business for up to 90 days without having to obtain a visa. All countries participating in the program have high HDI and most are regarded as developed countries.

In the U.S. territory of Guam, located in the western Pacific Ocean, the U.S. federal government has implemented a Guam-specific Waiver Program. As an insular area of the United States, entry requirements for Guam are the same as any other U.S. destination. However, under this program, enacted in October 1988, nationals from several additional countries in Asia and the Pacific islands are permitted to enter Guam as tourists without a visa for up to 15 days. Travel is not permitted onwards to the mainland United States.

An employee has specialized knowledge if the knowledge is different from that generally found in the particular industry. Possible characteristics of an employee who possesses specialized knowledge including knowledge that is valuable to the employers competitiveness in the market place: knowledge of foreign operating conditions as a result of special knowledge not generally found in the industry; has worked abroad in a capacity involving significant assignments which have enhanced the employer's productivity, competitiveness, image or financial position: possesses knowledge which normally can be gained only through prior experience with that employer; or possesses knowledge of a product or process which cannot be easily transferred or taught to another individual.

While an influx of new residents from different cultures presents some challenges, the United States has always been energized by its immigrant populations. At the 1998 commencement address at Portland State University, U.S. president Bill Clinton voiced support for immigrants, including immigrants from Asia and Latin America when he said that America has constantly drawn strength and spirit from wave after wave of immigrants. They have proved to be the most restless, the most adventurous, the most innovative, and the most industrious of people.

Self-Employment in the U.S. Not Permitted TN: Members of Appendix 1603.D.1 professions who are self-employed outside the U.S. may pursue business relationships from outside the U.S. (contracts for services) with U.S. based companies and obtain TN status to engage in these prearranged activities in the U.S.

However, under TN classification an alien is not permitted to come to the United States to engage in self-employment in the United States,nor to render services to a corporation or other entity in which he/she is a controlling owner or shareholder. Other NAFTA Admissions Categories Nationals Canada and Mexico may also seek admission as B-1 (business visitor), E-1 (treaty trader),E-2(treaty investor),or L-1(intra-company transferee) non immigrants under NAFTA.This bulletin does not address those alternatives.