This article describes the flux-compression process for the production of a high-energy pulse, and identifies two classes of generator - one which produces high energy (MJ) and high current (MA) in an external load and the other which concentrates a magnetic field into a small volume at a high flux density (MG; 1MG = 10(2)T) and a high energy density (10(5) MJ/m(3)). For each class, a representative generator is described and various possible applications are explained.