System Validation is the field that studies the fundamentals of system communication and information processing. It is the next logical step in computer science and improving software development in general. It allows automated analysis based on behavioural models of a system to see if a system works correctly. We want to guarantee that the systems does exactly what it is supposed to do. The techniques put forward in system validation allow to prove the absence of errors. It allows to design embedded system behaviour that is structurally sound and as a side effect enforces you to make the behaviour simple and insightful. This means that the systems are not only behaving correctly, but are also much easier to maintain and adapt. ’Model process behaviour' is the follow up MOOC to 'Automata and behavioural equivalences'. This MOOC shows you how to model process behaviour, in particular protocols and distributed algorithms, dive deeper in the properties of system behaviour, and keep things simple to avoid a state space explosion. Reading material. J.F. Groote and M.R. Mousavi. Modeling and analysis of communicating systems. The MIT Press, 2014. This course is part 2 of the set of courses for System Validation. System Validation, as a set of courses, is part of a larger EIT Digital online programme called 'Internet of Things through Embedded Systems'.