The study of economic phenomena very often involves observation of a large amount of data that needs to be presented in a systematic manner and then used in a meaningful way to assess the situation and draw conclusions. Without the development of a suitable mathematical tool, it is often difficult to clearly present the situation and perform a meaningful analysis, even for small size problems. For example, a company that wants to monitor daily sales of its products through a retail network in several cities and use the data obtained in order to conduct various analyses can hardly do so without a systematic and transparent display of the data. Therefore, in this chapter we introduce the term matrix as well as basic types of matrices.