Anna Castelli Ferrieri (1918–2006) was an Italian architect and industrial designer whose work played a major role in shaping post-war modern design and the development of plastic furniture. After graduating in architecture from the Politecnico di Milano in 1943, she became part of the generation of designers who helped rebuild and redefine Italian design in the decades following World War II. In 1949 she co-founded the company Kartell with Giulio Castelli, where she later served as artistic director and became one of the first designers to explore the architectural and structural potential of plastics in furniture and domestic objects. Rather than treating plastic as a cheap substitute for traditional materials, Ferrieri approached it with a rigorous architectural mindset, emphasizing durability, modularity, and precise industrial production. Her designs are characterized by clean geometric forms, rational construction, and a focus on everyday functionality, reflecting the principles of modernist design. Among her most famous works is the Componibili Storage Units introduced in 1969, a modular cylindrical storage system designed for flexible living spaces that became an international design icon and remains in continuous production today. Through her work with Kartell and her influence in the broader design community, Ferrieri helped establish plastic as a legitimate and innovative material in modern furniture design, leaving a lasting impact on contemporary industrial design.