The review is aimed at calling attention to a new method of investigation of magnetism, photoelectron measurement of the polarization. This method, developed at a juncture of the photoeffect and of magnetism, is of interest from the point of view of studying the properties of magnets as well as developing sufficiently intense sources of polarized electrons, which are needed for a number of problems in highenergy physics. A procedure is considered for successful experiments on the measurement of the polarization of photoelectrons. Detailed descriptions are presented of the results of measurements made on polycrystalline and disordered films of transition metals, rare-earth ferromagnets, as well as films and single crystals of chalcogenides and pnyctides. The available results, which agree well with the theoretical concepts for chalcogenides and pnyctides and which indicate the need for further development of both the theory and experiment for transition metals, confirm the undisputed value of the photoelectron polarization method. An already developed pulsed source of polarized electrons based on the photoeffect from EuO is described. (The literature through September 1975 is used).