Nine letters on art, written to friends from exile in France in the 1980s. Starting from earlier materialist approaches to art, Negri relates artistic production to the structures of social production characteristic of each historical era. This enables him to define the nature of both material and artistic production in the era of post-modernity and post-Fordism - the era Negri characterizes as that of immaterial labour. Negri then seeks to define artistic beauty in this new era, and this he does in terms of concepts that have become fundamental to his thinking - singularity, multitude, abstraction, collective work, event, the biopolitical, the common. Art is living labour, and therefore invention of singularity, of singular figures and objects. But this expressive act only achieves beauty when the signs and language through which it expresses itself turn themselves into community, when they are contained within a common project. The beautiful is not the act of imagining, but an imagination that has become action. Art, in this sense, is multitude.