During the mid-twentieth century, Latin American artists working in several different cities radically altered the nature of modern art. Reimagining the relationship of art to its public, these artists granted the spectator a greater role than ever before in the realization of the artwork. The first book to explore this phenomenon on an international scale, Abstraction in Reverse traces the movement as it evolved across South America and parts of Europe. Alexander Alberro demonstrates that artists such as Tomas Maldonado, Jesus Soto, Julio Le Parc, and Lygia Clark, in breaking with the core tenets of the form of abstract art known as Concrete art, redefined the role of both the artist and the spectator. Instead of manufacturing autonomous artworks prior to the act of viewing, these artists presented a range of projects that required the spectator in order to be complete. Importantly, as Alberro shows, these artists set aside regionalist art in favor of a modernist approach that transcended the traditions of any nation-state. Along the way, the artists fundamentally altered the concept of the subject and of how art should address its audience, a revolutionary development with parallels in the greater art world.