This book changes the emphasis in the traditional ordinary differential equations (ODE) course by using a mathematical software system to introduce numerical methods, geometric interpretation, symbolic computation, and qualitative analysis into the course in a basic way. Includes concise instructions for using Mathematica on three popular computer platforms: Windows, Macintosh, and the X Window System. It focuses on the specific features of Mathematica that are useful for analyzing differential equations, and it also describes the features of the Mathematica "Notebook" interface that are necessary for creating a finished document.