This book's discussion of a broad class of differential equations will appeal to professionals as well as graduate students. Beginning with the structure of the solution space and the stability and periodic properties of linear ordinary and Volterra differential equations, the text proceeds to an extensive collection of applied problems. The background for and application to differential equations of the fixed-point theorems of Banach, Brouwer, Browder, Horn, Schauder, and Tychonov are examined, in addition to those of the asymptotic fixed-point theorems. The text concludes with a unified presentation of the basic stability and periodicity theory for nonlinear ordinary and functional differential equations.