ABSTRACT
This chapter begins with a simple definition of a model along with why models are so important when trying to mathematically and conceptually explore a natural or man-made system. Some of the major standard types of models are considered and explained, with a deeper focus on mathematical systems modeling. Simply put, a model is a representation of “reality.” It serves as a stand-in for an actual system, physical entity, process, natural phenomenon, and more. Typically, models are used in industry, engineering, economics, advertising, and more in order to predict system response for specific input. It is essential to observe that some of the model categorizations can overlap, particularly with high-level classifications such as science and engineering models. Microscopic level models focus on individual entities or a collection of individual entities. Macroscopic level models are concerned with society, the state of society, or a group treated as one entity.
