The American sculptor Alexander Calder (1898-1976) was blessed with several kinds of genius. He was brilliant at the hands-on part, able to think incisively in several materials. He was innately cosmopolitan, a natural stylist and a bit of a sponge, swift to absorb and make his own the best of both the past and the present. He was an entertainer who aimed to please without pandering, to reconcile modernism and popular art, with assists from folk and what was then called primitive art.