“My fan mail is enormous,” Alexander Calder once said, humbly adding, “Everyone is under six.” An artist and an engineer, Calder invented the mobile—the infant’s fascination—and crafted whimsical wire sculptures of circus scenes. It all appears tenderly simple, but as the exhibition title makes clear, Calder’s sense of form, mass, and movement was radical, too. Australia’s first Calder retrospective surveys a groundbreaking career with nearly 100 pieces. —C.J.F