[en] The purpose of any technique for solidification of high-level liquid wastes is transformation of a solution of fission products of known type into a solid product which has been studied in the laboratory. The process used must therefore permit fabrication of the desired product. The author discusses the techniques used in the fabrication of: calcinates, glass-metal composites, modified-calcinate-metal composites, and glasses or products of strong glassy phase. (Auth.)