"The task of presenting a systematic, orderly, and accurate account of economic analysis is identical with the task of preparing the material for teaching. It must be emphasized, however, that the purpose of this work is not primarily to entertain the student, or to enable him to regurgitate appropriate material into examination books, or to learn a few pat phrases, or to indoctrinate him with an abstract discipline which he will never use. Economics is like photography in this respect, that under-exposure is less desirable than no exposure at all."