Key Message: Fundamentals of Differential Equations presents the basic theory of differential equations and offers a variety of modern applications in science and engineering. Available in two versions, these flexible texts offer the instructor many choices in syllabus design, course emphasis (theory, methodology, applications, and numerical methods), and in using commercially available computer software. Topics: Introduction, First-Order Differential Equations, Mathematical Models and Numerical Methods Involving First Order Equations, Linear Second-Order Equations, Introduction to Systems and Phase Plane Analysis, Theory of Higher-Order Linear Differential Equations, Laplace Transforms, Series Solutions of Differential Equations, Matrix Methods for Linear Systems, Partial Differential Equations, Eigenvalue Problems and Sturm-Liouville Equations, Stability of Autonomous Systems, Existence and Uniqueness Theory Market: For all readers interested in Differential Equations.