I. Introduction
Modern societies increasingly rely on the effective functioning of CIs to provide essential services such as telecommunications, transport, healthcare, energy, water and so on. It is thus crucial that CIs are resilient to natural and manmade assaults on its components. However, an important factor to note, from the perspective of resilience and risks, is the fact that the components within the CI are typically interconnected and dependent on each other in various ways that make it difficult to fully know the potential impact of failures. Furthermore, when we factor in the typical scale and complexity of modern CIs, determining the resilience of the infrastructure to attacks can be daunting. Even when we do know the dependencies that exist within the CI at a point in time, CIs are by nature emergent, which means that their organic growth and evolution may lead to unforeseen and subtle interdependencies, which can introduce new single-points-of-failure and pose other systemic risks.