Two of the most important American sculptors of the 20th century, Alexander Calder (1898-1976) and David Smith (1906-65) pushed sculptural practice in metal to new heights over the course of their careers. Bringing together pivotal sculpture of a historic moment in American art history, this monograph also features photographs from Italian Ugo Mulas, who met both sculptors in Spoleto in 1962 and documented them throughout his life. This publication is released on the occasion of an exhibition at Hauser & Wirth Zürich from June 10 to September 17, 2017.