Abstract
In the history of controlled thermonuclear fusion, there have been no ideas comparable in beauty and conceptual significance with that of the stellarator. The idea behind this device is the general concept of toroidal closed magnetic configurations which is the basis of the theory of magnetic plasma confinement in toroidal systems. It has engendered such important concepts as the magnetic surface, rotational transform and shear of magnetic field lines, the average magnetic well, the separatrix and island structure of magnetic surfaces, stochastization of magnetic field lines, the divertor, etc., and it has become an integral and fundamental part of the physics of high-temperature plasmas.