Thomas Annan was one of the first photographers to take his camera into the streets and direct his attention toward the working class. In the 1860s and ’70s, Annan photographed life in the tenements and narrow side streets of Glasgow with a sense of empathy and mission. This work made him a progenitor of the social documentary and street photography that became hallmarks of the twentieth century. The City of Glasgow Improvement Trust funded Annan’s project to petition for better living conditions. His ability to capture atmospheric light streaming into cramped alleys lent his photographs an emotional charge that made them ideal tools for advocacy.