The problem of rare-metal mineralization of pegmatites is an object of lively discussion. One group of researchers, mostly sharing the genetic ideas of A. E. Fersman, continues to defend the idea of the existence of a specific “pegmatite melt-solution”. It is assumed that the main mass of rare-metal compounds was contained in this “melt-solution” during its introduction into the host rocks. The formation of pegmatites (and rare-metal minerals in them) is represented as a process of successive crystallization of the melt, sometimes accompanied by autometasomatic transformations of early crystallization products under the influence of still liquid residue. The possibility of new portions of postmagmatic solutions entering the crystallizing pegmatites is admitted. However, the participation of these solutions in the occurrence of rare-metal mineralization seems to be limited.