This text presents a coherent and systematic exposition of the mathematical theory of the problems of optimization and stability, both of which are central to economic analysis. Through extensive use of economic examples, the authors provide the economist with a feel for the kinds of mathematical techniques most useful for dealing with particular economic problems. Although the text deals with fairly advanced material, the mathematical prerequisites are minimized by the inclusion of an integrated mathematical review designed to make the text self-contained and accessible to the reader with only an elementary knowledge of calculus and linear algebra.