Surveillance was once restricted to wartime reconnaissance photography (such as Harold Edgerton's pictures made in preparation for D-Day), or to tailing suspected spies during the cold war, or recording antiwar demonstrators in the 1960s and 1970s. Now, surveillance cameras proliferate everywhere, from national borders to banks, from apartment-building lobbies to street-corner traffic lights. The surveillance cameras that once were used primarily to identify the perpetrator in the act of a crime or to survey the potential "criminal" watch us as well.

Identification photographs are on our driver's licenses, our passports, and are often added to our bank cards to prevent misuse by an unauthorized signer. The early twentieth-century portraits of Peruvian miners, the identification pictures of Algerian women, and the photographs of Cambodians held by the Khmer Rouge were also made ostensibly for reasons of identification. But, as in these latter cases, it is not always evident at the moment a picture is taken what purpose it may ultimately be made to serve.