Hysteretic Behavior of Nucleation-Controlled Magnets is a special issue of Physics Reviews journal. Different patterns of hysteretic behavior of nucleation-controlled magnets can be simulated assuming different distributions of a few phenomenological parameters characterizing properties of individual grains. This review describes the correlation between these microscopic parameters and the magnetic properties. The authors also discuss the parameters of grain hysteresis of various sintered and rapidly quenched magnets and provide details of the magnetization process.