A REVIEW OF THEORY AND EMPIRICAL RESEARCH ON "THE LEARNING BY DISCOVERY HYPOTHESIS," AND RELATED LITERATURE ON CONCEPT-LEARNING AND PROBLEM-SOLVING, WAS PREPARED FOR A CONFERENCE IN NEW YORK CITY, 1965. RECENT CURRICULAR ACTIVITIES IN THE SUBJECT AREA WERE DESCRIBED. ATTEMPTS WERE MADE TO IDENTIFY INDEPENDENT AND DEPENDENT VARIABLES AND THE EXTENT OF RESEARCH IN THE SUBJECT AREA, AND TO DESCRIBE RELATED RESEARCH ON CONCEPT-LEARNING, PROBLEM-SOLVING, AND TRANSFER. RESULTS FROM THESE EFFORTS WERE DISCUSSED, AND SOME IMPLICATIONS FOR FURTHER RESEARCH ON LEARNING BY DISCOVERY WERE PRESENTED. (JM)