Images have become a source of knowledge and persuasion as powerful as the written word. And yet the image, as it manifests itself in painting, cinema, journalism, TV and photography, remains an enigmatic device. This text provides a theoretical account of the image, centred around five major questions - what does it mean to see an image? Who watches the image? How is the relationship between viewer and image regulated? How does the image "represent" the real world? Why do we classify some images as art?