- M. : World, 1971. — 121 s. Translated from English by B. M. With a foreword by Arnold B. and . The author, a well-known American mathematician, is already familiar to the Soviet reader from the translations of the books Morse Theory and the Theory of h-cobordism (The World, 1965 and 1969). His new book is devoted to the study of the topological structure of surfaces of the level of the analytical function of several complex variables in the vicinity of the point at which the gradient of the function turns to zero. Such a problem arises in various fields of mathematics, as well as in theoretical physics. The abundance of examples, the presence of drawings, the clarity and geometry of the presentation make the book available to senior students . Foreword to the Russian edition . Foreword by .