This text presents new modelling and analysis techniques for the description of discrete event dynamic systems, emphasizing timing and synchronization aspects. The volume begins with a study of the areas of applications and relationships between graph theory, petri nets and algebras. It then goes on to discuss deterministic discrete event systems, stochastic discrete event systems and open problems. This class of synchronized system finds its main current industrial applications in the modelling, optimization and control of communications networks and architectures, as well as manufacturing systems.