The plans for a field test of teaching tenth grade plane geometry through transformations is described. Text and homework materials have been written, and teachers have been trained. Eight intact classes are now being taught utilizing the materials. Data to be collected will include: (1) teacher descriptions of the course via questionnaire; (2) teacher assessment of course appeal to students and rate and level of comprehension on the part of the students, (3) student self-assessments as to comprehension and interest in the materials and (4) achievement test scores. The students will be classified by sex and I.Q. and data will be analyzed using a two-way analysis of variance with null hypothesis that the eight group means are not significantly different. A complete list of definitions, axioms, postulates, and theorems used in the materials is included. (JG)