In recent years a large variety of types of in-service courses have been devised in many countries to meet a wide range of needs and conditions as economically as possible. It is therefore difficult to suggest any simple classification of in-service courses. How does one define a “short” course? And may not an inservice “project” or “programme” be made up of a variety of different elements - “short” and “long” courses; weekend conferences; radio study groups; correspondence assignments and so on?