Susan Sontag's career was cross-disciplinary and devoted to challenging injustice with her own brand of human rights activism. On Photography picks up Sontag's earlier ideas on the excesses of American culture, which she would return to later in her career? On Photography was Sontag's way of working through this traumatizing experience, her attempt, in the words of art historian Jae Emerling "to grapple with these images by addressing their aesthetic existence". On Photography launched careers in photographic criticism, supported the academic inroads of French theory, and made photography a suitable object of intellectual investigation. With the enormous expansion of digital images, Sontag's fears about the medium are still prescient today. Sontag's ideas were articulated rhetorically and were not scholarly enough to be disproved. The power of that rhetoric was inspirational. Sontag's non-fiction writing has appealed to many different audiences. Much of her film criticism is still used today in universities.