As a result of well-organized co-operation in controlled nuclear fusion research, each day sees the rapid spread of knowledge and results gained in this field throughout the world. Thus, the knowledge is steadily accumulating. However, perhaps for psychological reasons, views on the status of the problem change rather abruptly. With the same corpus of knowledge, we are now beginning to recognize clearly the nature of a problem which was shrouded in mist only yesterday, and yet tomorrow we may be unable to believe that the mist ever existed. One eminent English writer, I believe, neatly expressed this thought in an aphorism to the effect that every truth enjoys only a brief moment of triumph between one period during which it is rejected as a paradox and another during which it is accepted as trivial. To experience these brief moments, we gather together at IAEA Conferences which afford us so much joy.