Chapter 1 covered the main simulation methods of discrete-event simulation (DES), agent-based simulation (ABS) and system dynamics (SD). In many circumstances, it may be that one of these methods is appropriate to address a problem situation. The decision on which method to use will be determined by the experience and preferences of the modeller, as well as the problem situation to be addressed. It may also be appropriate to use a combination of these methods. This chapter covers different design options for combining these methods and then examines their characteristics to show when they might be applied to a particular problem situation.