This text is designed for the standard post-calculus course in elementary differential equations. It is a brief, one-semester treatment of the basic ideas, models, and solution methods. The book, which serves as an alternative to existing texts for instructors who want more concise coverage, emphasizes graphical, analytical, and numerical approaches, and is written with clear language in a user-friendly format. It provides students with the tools to continue on to the next level in applying differential equations to problems in engineering, science, and applied mathematics. The topics include: * separable and linear first-order equations; * autonomous equations; * second order linear homogeneous and nonhomogeneous equations; * Laplace transforms; * linear and nonlinear systems in the phase plane. Many exercises are provided, in addition to examples from engineering, ecology, physics, economics, and other areas. An expanded section on the required linear algebra is presented, and an appendix contains templates of Maple and MATLAB commands and programs which are useful in differential equations.