On Photography is a 1977 collection of essays by Susan Sontag. It originally appeared as a series of essays in the New York Review of Books between 1973 and 1977. In the book, Sontag expresses her views on the history and present-day role of photography in capitalist societies as of the 1970s. Sontag discusses many examples of modern photography, among these, she contrasts Diane Arbus's work with that of Depression-era documentary photography commissioned by the Farm Security Administration. ([Wikipedia][1])

[1]: http://en.wikipedia.org/wiki/On_Photography