Excerpts from the report Summary: The very seasonal nature of work required for agricultural production, particularly for the more labor-intensive crops, has generated the supplementary farmworker system in the United States. This system, intensified in recent years by technological innovation, has resulted in a large and fluctuating seasonal demand for supplementary farm labor. Supplementary farmworkers are classified into two major groups, domestic and foreign. Domestic workers are further categorized as local and migrant, depending upon their mobility; foreign workers are classified according to nationality. Except in the 1930's, legally imported foreign workers have made up some portion of the supply of supplemental workers for many decades. From its enactment in 1951 to its termination at the end of 1964, Public Law 78 was the chief law enabling entry of these workers. Termination of this law has caused concern in agriculture and in related segments of the economy. The number of Mexican workers (commonly known as braceros) contracted annually under P.L. 78 declined from a high of 445,197 in 1956 to 186,865 in 1963. Only 16,132 employers used braceros in 1963; the number contracted during the year constituted about 5.9 percent of the total number of persons who did supplemental farmwork. The average number of Mexicans employed during the year accounted for about 0.7 percent of the farmwork force. Thus, they made up a very small portion of the national farm labor force.