Book excerpt: Organized by ICP Curator Carol Squiers, 'What Is a Photograph?' will explore the intense creative experimentation in photography that has occurred since the 1970s. Conceptual art introduced photography into contemporary art making, using the medium in ways that challenged it artistically, intellectually, and technically and broadened the notion of what a photograph could be in art. A new generation of artists began an equally rigorous but more aesthetically adventurous analysis, which probed photography itself - from the role of light, color, composition, to materiality and the subject. 'What Is a Photograph?' brings together these artists, who reinvented photography.