For over a century and a half, photography has been the most popular and widespread means of making images. The first and primary tool of photography is the camera, and changes in the medium and its applications are often attributed to technical developments in making, reproducing, and distributing photographs. Equally if not more significant, however, have been changes in the ways people think about photography, including ideas about what and how photographs represent, and the roles they have played in social, political, and economic life. This article examines developments and conflicts in the idea of photography within a historical framework of changing cultural practice.