Introduction There are (at least) three reasons to model and simulate a social system. First, to understand and explain how the social system works, for example, to investigate the effect of policy change on a large population, or to understand some other property or phenomenon, such as a nancial system (Christensen et al. 2002), or the spread of information in a social network (Draief and Ganesh 2010). Second, to formalize human methods of problem-solving as a source and inspiration for developing computational systems to address engineering challenges (Edmonds et al. 2005), an example being trust in open multiagent systems (CastelfranchiIntroduction ...................................................................................................... 43 Methodology ..................................................................................................... 44 Examples of social systems ............................................................................. 45Distributive Justice: Formal model ........................................................... 46 Kyoto Protocol: Formal model ....................................................................... 48 Presage2 ............................................................................................................. 50Architecture .................................................................................................. 52 Operational basis ......................................................................................... 55Worked examples ............................................................................................. 56 Distributive Justice: Operational model in Presage2 ............................. 56 Kyoto Protocol: Operational model in Presage2 ..................................... 59Simulating sociotechnical systems ................................................................ 61 Summary and conclusions .............................................................................. 63 References .......................................................................................................... 64and Falcone 1998). Third, to represent and reason about the sociological concepts involved, as the basis for implementing sociotechnical or cyber-physical systems (Ferscha et al. 2012; Hoffman et al. 2009), in which the technical components understand the same concepts as the human ones (commonly required in workow, legal systems, serious games, etc.).