Accumulated scientific and industrial experience shows convincingly that the REMs have certain physicochemical properties that ensure a bright future for these metals in applications to metallurgy and to machinery and instrument construction. It indicates the need for considerably broadening and intensifying the scientific study and experimental work in this direction. First in importance is the determination of constants and of constitutional diagrams for the metals and their alloys and compounds. Then must come the determination of the effects of the REMs and yttrium on the structure and properties of alloys of all bases, and of the most effective and economical application of the REMs in the iron, steel, and nonferrous and light alloy industries.