The two-volume work is intended to function as a textbook for graduate students in economics as well as a reference work for economic scholars. Assuming only the minimal mathematics background required of every second-year graduate student in economics, these two volumes provide a self-contained and careful development of mathematics through locally convex topological vector spaces, and fixed-point, separation, and selection theorems in such spaces. Volume One covers basic set theory, sequences and series, continuous and semi-continuous functions, an introduction to general linear spaces, basic convexity theory, and applications to economics. Volume Two introduces general topology, the theory of correspondences on and into topological spaces, Banach spaces, topological vector spaces, and maximum, fixed-point, and selection theorems for such spaces.