The concept of “risk” lies at the heart of decision-makingDecision-making processes across industries, yet its interpretation and application often vary depending on the context, objectivesObjective, and stakeholderStakeholder perspectives. This lesson seeks to demystify the multifaceted nature of risk by exploring its definition, description and measurement. Building on this, the purpose of risk assessment is highlighted as it is easily forgotten. The lesson further explores the crucial frameworks of the Norwegian, UK (United Kingdom) and EU (European Union) regulations and relevant standards, which provide structured methodologies and compliance requirements to ensure systematic and consistent risk managementRisk management practices. After that, uncertaintiesUncertainties and sensitivities, which are tightly linked but distinct concepts, are discussed. This discussion extends to black swan risks, which has attracted significant public attention. The authors argue that the concept of black swan risk should be restricted to the realm ofUnknown unknowns “unknown unknowns”. Lastly, a key focus is placed on Human and Organizational Factors (HOFs)Human and Organizational Factors (HOFs) and their significant influence on risk. By synthesizing these elements, the lesson aims to equip readers with a holistic understanding of risk.