TWENTY-SEVEN STUDIES ON INTERCLASS GROUPING AT THE ELEMENTARY LEVEL ARE SUMMARIZED. IT IS POINTED OUT THAT THE SUMMARY IS NEITHER EXHAUSTIVE NOR DELIBERATELY SLANTED. STUDIES POORLY DONE IN TERMS OF SAMPLE OR TREATMENT WERE NOT INCLUDED. THE STUDIES ARE GROUPED ACCORDING TO TWO QUESTIONS--(1) IS ACHIEVEMENT INCREASED BY GROUPING AND (2) ARE STUDENTS' ATTITUDES AFFECTED BY GROUPING. A SERIES OF QUOTATIONS FROM THE RESEARCH STUDIES IS GIVEN TO PROVIDE A BRIEF SURVEY OF THE LITERATURE. A BIBLIOGRAPHY IS INCLUDED. (RH)