The challenges in  Complex Engineered Systems;  Complexity Science;  Natural Complex Systems will focus investigations into methods for risk and resilience assessment of complex systems, such as cities, National Infrastructure, and Complex Products. But as these systems are complex (co-evolving, adapting, non-linear, dynamic, etc.) it follows that such risk and resilience assessments are limited, uncertain and dependent on unfolding futures. The evaluation of uncertainty is essential to understanding these critical systems. The purpose is to improve the understanding and management of uncertainty evaluation in complex engineered systems.