The immigration of approximately 57,000 scientists and engineers to the United States during the 1966-70 period prompted questions as to the benefit to the United States, the implications for countries of origin, and the reasons behind the movement. This report is a broad survey of immigrant scientists and engineers conducted by the National Science Foundation and is essentially divided into two parts. Section 1 discusses the immigrants' appraisals of 17 factors deemed critical in leading to the immigration of scientists and engineers to the United States. Section 2 discusses how the immigrants' views of key aspects of living and working in the United States relative to their country of origin (e.g., social conditions and economic benefits) have changed since their entry into the United States. Complete technical notes, statistical tables, reproduction of covering letter, questionnaire and a list of occupations are also included. (Author/BR)