Celebrated for mobiles and stabiles that enliven city squares and museums around the world, Alexander Calder (1898-1976) is not widely recognized as a portraitist. Throughout his career, however, Calder created portraits of a wide variety of subjects: well-known entertainment and political figures, sports stars, artist friends, family members, and himself. Some of these portraits are traditional likenesses in oil on canvas or ink on paper, but most...