The nuclear fusion R & D programs underwaytoday in various countries are generally directed toward the near-term objective of scientific feasibility by any of several concepts involving either magnetic or inertial confinement of the plasma. In the last few years, the level of support for fusion research has markedly increased, first, because of the significant technical advances made in the field, and, more recently, because of the high priorities given to such work as a result of the world energy crisis.