Advances in Physical Sciences, 1997, t. 167, No. 2, s. 19137 . In theory, the electrodynamic properties of various magnetically ordered media are investigated. Two types of magnets are considered: ferromagnets and antiferromagnets, and how the properties of the metal are modified due to the presence of a magnetic subsystem. Within the framework of the traditional concept of quasiparticles, various types of elementary excitations, magnetic polaritons, magnetostatic waves, magnetons . are investigated. In a wide range of frequencies, it is shown how the law of dispersion of quasiparticles depends on the ratio between characteristic frequencies of different nature, electric and magnetic. Much attention is paid to the issues of statistical thermodynamics and kinetics of magnets . Considered the possibility of Bose-Einstein condensation in the gas of magnons. Kinetic theory of electronic attenuation of magnetostatic waves in ferromagnetic metal. The laws of dispersion of surface polaritons . are studied in detail Examples of solving spatially inhomogeneous problems when taking into account spatial dispersion. Spatial dispersion has been shown to be particularly important in the case of antiferromagnets.