Achille and Pier Giacomo Castiglioni were Italian architects and designers born into a creative Milanese family, influenced by their father, sculptor Giannino Castiglioni. After studying at the Politecnico di Milano, they joined their brother Livio in founding the Castiglioni Studio. Their work is defined by functional minimalism and inventive reinterpretations of everyday objects, spanning furniture, lighting, and exhibition design. Livio Castiglioni left the practice in 1952, and the remaining two brothers continued working as a team until Pier Giacomo’s death in 1968. The duo’s designs were instrumental in defining the playful intelligence for which Italian design became known in the second half of the 20th century. They received multiple Compasso d’Oro awards and collaborated with brands such as Flos, Zanotta, and Alessi. Their work is held in major museum collections, including MoMA in New York and the Victoria and Albert Museum in London. Achille continued designing independently and later taught industrial design at the Politecnico di Milano until 2002.