The chapter introduces the circular economy as an alternative systemic model to the linear paradigm, explaining its theoretical foundations, key principles (eco-design, regeneration, efficient use of resources) and environmental, economic and social benefits. One section is dedicated to European regulatory developments, from the CEAP to the Circular Economy Package II, to national plans and the PNRR. It highlights how circularity represents a strategic infrastructure for industrial competitiveness, resilience and resource security.