This book looks at the problem of the mathematical modelling, numerical simulation and optimal control of the equilibrium of plasma in a Tokamak (a piece of equipment used for controlled nuclear fusion of atoms of low mass). Among the problems considered are the stationary problem of the axisymmetric equilibrium of the plasma, identification and control of its frontier, thermal diffusion in the plasma, and the stability and dynamic control of movements in the plasma. The author compares the algorithms available for the numerical solution of these problems for the different types of Tokomak in use or under development.