Imagine Soldiers reacting to an unpredictable, dynamic, stressful situation on the battlefield. How those Soldiers think about the information presented to them by the system or other Soldiers during this situation – and how well they translate that into thinking into effective behaviors – is critical to how well they perform. Importantly, those thought processes (i.e., cognition) interact with both external (e.g., the size of the enemy force, weather) and internal (e.g., ability to communicate, personality, fatigue level) factors. The complicated nature of these interactions can have dramatic and unexpected consequences, as is seen in the analysis of military and industrial disasters, such as the shooting down of Iran Air flight 655, or the partial core meltdown on Three Mile Island. In both cases, decision makers needed to interact with equipment and personnel in a stressful, dynamic, and uncertain environment. Similarly, the complex and dynamic nature of the contemporary operating environment faced by the United States Army makes it clear that mission performance depends on systems that are engineered to ensure that the complex systems of people and technology (i.e., sociotechnical systems) can sustain high levels of cognitive performance needed for succeed. This session overview highlights cognitive engineering and illustrates how modeling and simulation can address different aspects of this important field.