a. O-1A

Pertains to a person who "has extraordinary ability in the sciences, arts, education, business or athletics which has been demonstrated by sustained national or international acclaim." 8 C.F.R. §214.2(o)(1)(ii)(A)(1)

b. O-1B
If in a motion picture or TV production, the person must have "a demonstrated record of extraordinary achievement." Person needs to demonstrate that his or her achievements have been recognized in the field "through extensive documentation." 8 C.F.R. §214.2(o)(1)(ii)(A)(2).

c. The Service interprets the statute to encompass "any field of endeavor" including craftsmen and lecturers. Memo, Weinig, Acting Asst. Comm.

d. One must seek to enter for the purpose of continuing the type of work, but there is no requirement that the person is coming to the U.S. to perform services requiring a person of O-1 caliber. 

e. Dual intent recognized, as there is no foreign residence requirement but there is a requirement that there be a temporary intent to remain. 

a. This status is only for a person accompanying and assisting an O-1 artist or athlete in the artistic or athletic performance for a specific event or events so long as: (1) S/he is an integral part of such actual performance.
(2) S/he has critical skills and experience with the O-1 that are not of a general nature and which cannot be performed by other individuals.
(a) For motion picture or TV productions, person has skills and experience which are not general, which are critical and which are based on a pre-existing long-standing working relationship.
(3) S/he has foreign residence which s/he has no intention of abandoning.