"This study discusses the political, economic, and security aspects of the problem of illegal migration from Mexico into the United States. The problem is defined in terms of forces which tend both to pull Mexican citizens into the United States and to push them out of Mexico. Serious conditions of unemployment and underemployment in Mexico create conditions of extreme hardship which force people to seek alternative ways to support themselves and their families. All they must do is cross an undefended border almost 2,000 miles long, where jobs with much higher pay are waiting. It is explained that the migration of significant numbers of Mexican citizens into the U.S. provides Mexico with an important safety valve to relieve the political and economic pressures of high unemployment and a generally distressed economy. It is also noted that there is an important human dimension in this problem which is frequently overlooked."