Moscow, "Mir", 1972 . , -316 s. The book contains a translation of two chapters of the monograph "Superconductivity" edited by P. Parks dedicated to superconductivity of degenerate semiconductors and transition metals. These are the first in the world literature and almost exhaustive reviews on this topic, the authors of which focused on the analysis of specific materials and the study of the relative role of various mechanisms in the phenomenon of superconductivity. On the basis of existing representations, a large amount of factual material accumulated on these issues has been analyzed and explained, at least qualitatively. The book is of interest to specialists in the field of solid state physics, physics of metals and semiconductors.