ACCORDING TO ESTIMATES, THERE ARE 2 MILLION ALIENS IN THE UNITED STATES, A HIGH PERCENTAGE OF WHICH ARE OF MEXICAN NATIONALITY. MOST OF THESE PERSONS COME TO THE U.S. IN HOPES OF FINDING WORK, BUT THEIR PRESENCE IS THOUGHT TO CONTRIBUTE TO A HIGH UNEMPLOYMENT RATE, LOW WAGE LEVELS, POOR WORKING CONDITIONS, DIFFICULT OPERATION OF MANPOWER PROGRAMS, INFLATED WELFARE COSTS, EMPLOYEE ORGANIZATION PROBLEMS, AND ALIEN EXPLOITATION. FOR THE PURPOSE OF THIS STUDY, DATA WERE GATHERED ON MANPOWER EXPENDITURES, APPREHENSIONS, DEPORTATIONS, PROSECUTIONS, AND ADMINISTRATIVE PRACTICES. DATA SOURCES INCLUDED GOVERNMENT PUBLICATIONS, UNPUBLISHED REPORTS FROM THE IMMIGRATION AND NATURALIZATION SERVICE, PERSONAL OBSERVATION, INTERVIEWS, CORRESPONDENCE, AND MEDIA REPORTS. THE DEL RIO-EAGLE PASS AREA IN TEXAS WAS A SPECIAL AREA OF FOCUS. IN THE PAST 2 YEARS, THE IMMIGRATION AND NATURALIZATION SERVICE HAS NOT INCREASED ITS TOTAL PERSONNEL AUTHORIZATION, BUT HAS CONCENTRATED INSTEAD ON EQUIPMENT AUTHORIZATIONS. IT WAS FOUND THAT THE GEOGRAPHIC BOUNDARIES OF IMMIGRATION DISTRICTS, BORDER PATROL SECTORS, AND U.S. COURT DISTRICTS RARELY COINCIDE, RESULTING IN A DIFFICULT MANAGEMENT SITUATION WHEN COORDINATION OF OFFICERS FROM MORE THAN ONE BRANCH OF THE AGENCY IS NEEDED. PROSECUTION OF ALIENS HAS BEEN INEFFECTIVE BECAUSE OF THE PROCEDURES WITHIN THE BORDER PATROL AND THE APPARENT LOW PRIORITY GIVEN TO IMMIGRATION VIOLATIONS BY U.S. ATTORNEYS. THE PATROL OFFICERS ARE TOO OFTEN CONCENTRATED AT THE MEXICAN BORDER AND ARE VERY SCARCE IN THE INTERIOR TOWNS WHERE ALIENS ARE LIKELY TO CONGREGATE. LEGISLATION TO PENALIZE THOSE WHO ILLEGALLY EMPLOY ALIENS IS NEEDED AND IN PROCESS. DEPORTATION IS NOT AN EFFECTIVE DETERRENT TO SIMPLE ENTRY WITHOUT INSPECTION, BUT THE PROCEDURE SHOULD BE CONTINUED. RECOMMENDATIONS INCLUDE IMPROVING LEADERSHIP WITHIN THE PRESENT PROMOTION AND REASSIGNMENT PLAN, STREAMLINING THE AGENCY'S CHAIN OF COMMAND, AND ALLOCATING FUNDS IN PRIORITY AREAS RATHER THAN FOR VERY SOPHISTICATED EQUIPMENT. MORE ACCURATE ESTIMATES ON THE NUMBER OF ALIENS IN THE U.S. ARE NEEDED; STUDY ON THE SOCIOLOGICAL IMPACT OF MEXICAN ALIENS IN THE U.S. AND ON THE CLAIMS OF UNSKILLED LABOR SHORTAGES IN CERTAIN GEOGRAPHICAL AREAS OF THE COUNTRY WOULD BE APPROPRIAE. A REVIEW OF THE CURRENT LITERATURE ON THE SUBJECT, TABULAR DATA, AND NOTES ARE PROVIDED. A BIBLIOGRAPHY, EXTRACTS FROM CONGRESSIONAL HEARINGS AND REPORTS, AND CHARTS OF THE IMMIGRATION AND NATURALIZATION SERVICE ARE INCLUDED. (JSP)