The book "Media Theory" offers a comprehensive analysis of mathematical structures that model physical or biological systems. It explores how different states of a system are characterized by binary features and how these states differ from one another through minimal changes, such as the addition or removal of features. Using examples like solving a puzzle, it illustrates how states can be transformed. The authors, David Eppstein, Jean-Claude Falmagne, and Sergei Ovchinnikov, formalized these concepts within a semigroup-based framework that describes the transformation of states through specific messages. The two fundamental axioms that define the structure ensure that any state can be generated from any other state and that these transformations are consistent. This academic book is aimed at readers who wish to develop a deeper understanding of the mathematical foundations of media and system theory.