This lecture covers the concepts of risk, disaster risk reduction, capacity, and resilience, emphasizing the importance of science and technology in mitigating the impact of disasters. It explains how risk is calculated, defines disasters and disaster risk, and explores the types of losses caused by disasters. The lecture also delves into the significance of disaster risk reduction (DRR) in preventing and managing risks, highlighting the role of capacity and resilience in enhancing community preparedness. It discusses the terms capacity development, resilience, and long-term resilience, illustrating the evolution from short-term recovery to long-term risk reduction. Additionally, it addresses the relationship between DRR, climate change adaptation, and sustainable development, emphasizing the interconnectedness of these concepts.