Your invitation to the National Science Foundation was to testify concerning the impact of the immigration laws upon science. For the most part the effect of the immigration laws upon science is not substantially different from the effect upon other professional and scholarly activities. In the matters concerning the admission of foreign scientists as visitors, however, experience has demonstrated the existence of a problem of special concern to science and one in which the stake of this country is large. It is, therefore, to this special problem that I shall speak.