The radical project 'an Exhibit' emerged from a decade of testing the formats and possibilities of exhibition-making. A collaboration between two artists, Richard Hamilton and Victor Pasmore, and a critic and curator, Lawrence Alloway, the show was simultaneously an investigation into abstract environmental forms and a participatory experiment that would fundamentally transform the role of the viewer. Comprehensive documentation of the original exhibition is presented alongside coverage of other key projects from the era and contextualised through the detailed analysis of Elena Crippa. Archival texts conveying the different voices of 'an Exhibit's three creators and an essay from the time by David Sylvester are accompanied by new contributions by Martin Beck, Owen Hatherley and Lucy Steeds. This book addresses the diverse legacies of 'an Exhibit'- from its reverberations in contemporary art practice to its influence on urban design and social housing.