In the study of the chemical composition of the lunar soil, and in the future, the planets of the solar system, a special place is occupied by the X-ray isotope fluorescent analysis method (RHYMA). In the brochure, the participants in the creation of the RIFMA equipment used in the work of the Soviet Lunokhodov talk about the physical foundations of this method, and also give the results of chemical analysis of the lunar soil obtained using both this and other methods...