The Guaranteed Student Loan (GSL) program's current operations, legislative history, and growth are reviewed, along with research needs. GSLs are made by lenders to college students, and the federal government guarantees them and provides incentive payments to lenders and subsidy payments on behalf of students until loan repayment begins. Today, the GSL program is the largest single source of student financial assistance. In fiscal year 1982 over 3.5 million students will secure GSLs, and the average size of these loans will be over $2,100. The vast majority of GSLs are guaranteed by state guaranty agencies that administer the GSL program. These agencies are then reinsured by the federal government for loans. A major participant in the program has been the Student Loan Marketing Association, which provides a secondary market for GSL lenders. The following specific aspects of the program are examined: the in-school interest subsidy, the special allowance, defaults, trends in loan volumes, borrower rules, lender rules, program costs and the administrative aspects of the GSL program from the viewpoint of all participants. (SW)