In the given summarizing article, we present the most important aspects of the technique of studying disordered magnetic systems by the Mössbauer effect being developed by us for the broad circle of researchers in magnetism and Mössbauer spectroscopy. The potentialities of this technique in investigating local magnetic characteristics and spin structures of disordered magnetics are assessed by the interpretation of Mössbauer spectroscopy data of various classes of well-studied magnetics (Fe−Al, Fe-V). In the concluding part, we present original results of Mössbauer investigations of binary (Fe−Cr, Fe−Pd and Fe−Au) and quasi-binary (Fe−Pd−Au) alloys characterized by non-trivial macroscopic magnetic properties and complex magnetic phase diagrams.