Develops a regularity theory of solutions for a species of partial differential equations that arise in control theory and optimization. Extends the classical Schauder and Calder=n-Zygmund regularity theories for linear elliptic equations to the fully nonlinear context. Explains in detail all the techniques needed, but does not develop them to their greatest generality. Does consider fully nonlinear equations with variable coefficients. Annotation copyright Book News, Inc. Portland, Or.