The analysis of complex systems (CS) involves the use of different points of view so as to be able to understand the different aspects of the system’s entities, and to characterize their interactions. Modeling and simulating CS are activities where collaboration between researchers is the rule rather than the exception. Indeed, as a result of the complexity of studied systems, it is often essential to bring together different perspectives from different fields of study. Thus, the popular idea of a solitary researcher that is able to collect data, put together conceptual models and use these with computing tools, is gradually being replaced with that of an interdisciplinary group usually composed of thematicians, computer scientists and mathematicians. For such a group, the model (or the simulation) is at once: (1) the reason for their coming together, (2) their collective objective and (3) the basis for their collective work.