article reports, in part, an investigation conducted by the writer as a partial fulfillment of the requirements for the Ph.D. degree in the College of Education of the State University of Iowa. The assistance of Dr. Ernest Horn, under whose direction the study was conducted, is gratefully acknowledged.

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Leaders in mathematics education have long recognized that the elementary school teacher's Jack of mathematical background was a major deterrent to improvement of instruction in this curricular area. While a number of recommendations for improving the mathematics part of teacher-education programs were made before the new mathematics era,1 very little change in the mathematics preparation of elementary school teachers took place until after new mathematics began to be widely used in the elementary schools. Then, when teachers began to meet elements of strange new content, the need for additional mathematical knowledge became readily apparent.