Classical control theory is intrinsically linked to the frequency domain and the s-plane. The main drawback of classical control theory is the diculty to apply it in Multi-Input Multi-Output (MIMO) systems. Rudolf Emil Kalman (Hungarian-born American, May 19, 1930  July 2, 2016) is one of the greatest protagonist of modern control theory1. He has introduced the concept of state as well as linear algebra and matrices in control theory. With this formalism systems with multiple inputs and outputs could easily be treated.