This report gives background data and an overview of the development of the ECON 12 project, which was carried out in conjunction with the Developmental Economics Education Program (DEEP) grant from the Joint Council on Economic Education to the Contra Costa County (California) Department of Education. The program and its dissemination were considered a system, made up of three main parts: The ECON 12 course, evaluation instruments and procedures, and a teacher training program. The latter two were considered as vital as the course materials and the cognitive and behavioral objectives. Cooperation from the County Department of Education assured that trial courses and teacher participation contributed to effective course design. Materials are described and stages of lesson development are clarified. A section on teacher training outlines the chronological sequence of a basic introduction to economic theory, practicum sessions, and teacher supervision. The to-date summary indicates positive acceptance of the project during trial tests and satisfaction with the application of system development procedures to the design of the course. At the date of this report, Units I and II were completed (ED 040 100, 101), Unit III and optional units were due for completion in 1967. Revised editions were published in 1968 (ED 053 048, 049). Addison Wesley will be publishing the future editions. (JMB)