San Francisco gay radical sex photographer Mark I Chester documents gay men being sexual on the streets of South of Market. It is a love letter to the past and a dream for the future. South of Market is changing at an exponential rate. These images insist that gay men and gay leathermen are still an essential part of the history of these streets. They are part documentary, part fantasy, part fine art sexual portraiture on the street and part outlaw behavior. They believe that sex is an essential part of what it means to be gay.