A hands-on tutorial, covering interactive simulation of dynamical systems such as aerospace vehicles, power plants, chemical processes, control systems, and physiological systems. In practice, simulation experiments are employed for iterative decision-making, whereby programs are run, modified, and run again and again. It is very important to emphasize interactive simulation programming. To this end, the user-friendly Microsoft Windows 95 interface is combined with the DESIRE (Direct Executing Simulation) language. The first chapter introduces dynamical system models and the principles of differential-equation-solving problems. The following chapters provide a tutorial on effective simulation programming, with examples from physics, aerospace, engineering, population dynamics, and physiology. The remaining chapters provide more detailed programming know-how.