Ugo Mulas and Alexander Calder. A great photographer and a great artist bound by close friendship. The visible fruit of this relationship are the hundreds of photographs of the histrionic American artist, his family, his works, and his houses in Roxbury (USA) and Sache (France) taken by Mulas: a 'family album that showed the love for his work and the joy that his friendship gave me'. The carefully selected photographs presented, edited by Melina, Ugo Mulas' daughter and a well known photographer in her own right, evidences the role of unspoken art critic played by Mulas.As Argan writes, the photographer was able to capture 'with incredible delicacy the genetic affinity between the works and their creator, and at the same time their intimate contradiction, as if the lightness of the sculptures atoned for the sculptor's heavy bulk and their capriciousness matched his kind-hearted, unpredictable character, the nature of which is expressed by the tufts of his white hair, ever tousled by a non-existent wind'.Born into a family of artists, Alexander Calder (1898-1976) showed right from his infancy an approach to the manipulation of materials that was to change the course of modern art. An outstanding inventor of wire caricatures and animals (see, for example, his famous Circus), at the start of the 1930s Calder developed into the construction of abstract sculptures in which he soon included moving pieces. These sculptures, which he called mobiles, are among the most famous artworks of the twentieth century. In them, Calder 'took matter and transformed it into an image as light as a puff of air'. Ugo Mulas (1928-1973) was one of the greatest Italian photographers of the last century. His enormous interest in the world of art is attested by the photographs he took at the various Biennali in Venice between 1954 and 1972, and by his superlative recording of the art scene in New York, which he carried out in different stages between 1964 and 1967.