After a short conceptual/historical introduction about the notions of risk, hazard, danger and uncertainty, the chapter addresses through a genealogical perspective core ideas and key thinkers in the issue, from the post-war foundations to risk perception and risk culture approaches, from the risk society thesis and the gaining relevance of uncertainty to the most recent framework of risk as a rationality of government. The critical potential of the concept of risk is subsequently discussed, with special reference to neoliberal environmental regulation and a new generation of theoretical approaches.