The future is uncertain and our world is complex, ambiguous and dynamic. To approach this context, this chapter presents fundamental philosophical assumptions, as well as a range of key concepts, which all are central for managing risk and resilience for sustainable development. It introduces a coherent philosophical framework for understanding and addressing our world, which is intended to bridge between the various functional sectors and academic disciplines necessary for building a safe and sustainable society. It also introduces a comprehensive approach to the concepts of development, sustainability, risk, value, hazard, vulnerability, capacity and resilience, as well as laying the foundation for managing risk for sustainable development.