The EB-1 is a preference category for United States employment-based permanent residency. It is intended for "priority workers" and allows them to remain permanently in the US.
The visa is granted to three types of aliens:
EB-1A - Those with extraordinary ability in the sciences, arts, education, business, or athletics that has been demonstrated by sustained national or international acclaim and whose achievements have been recognized in the field through extensive documentation.
EB-1B - "Outstanding professors and researchers" who "are recognized internationally for their outstanding academic achievements in a particular field". They must also have "at least three years' experience in teaching or research in that academic area, and enter the U.S. in a tenure or tenure track teaching or comparable research position at a university or other institution of higher education" plus other conditions.
EB-1C - "Some executives and managers of foreign companies who are transferred to the U.S." They need to have been employed, during the last three years, for at least one year outside of the U.S. in a managerial position in the same company that is going to employ them in the U.S. or in a related company.