“I enrolled in this course merely to complete the college entrance requirements … Now I wish that I could study geometry all the rest of the time I am in high school.” The fifteen-year-old writer of the preceding statement had little interest or ability in mathematics. Early in the course he tried to explain a postulate by a highly-prized “picture of one.” With I.Q. (Terman) 98, he ranked in the third quartile of eighty-five tenth grade pupils who formed our experimental group. He kept a detailed notebook of theorems and daily assignments, written up in his own words. At the end of the year he confided that he had never seen inside a geometry book. He took the Cooperative Plane Geometry test, Revised Series Form Q, of the American Council of Education with a score of 25.5, about 40 per cent above the standard for the country as a whole.