Born in Cuba, Luis Medina immigrated to Miami after a multiyear tour of Europe in his teens. He relocated to Chicago in 1967 to study first sculpture, then photography, at the School of the Art Institute of Chicago. As a boy in Havana, Medina had, as he put it, “explored the brightest and darkest corners of that city . . . in search of ineffable essences, contradictions, and tragedies contained in anything human.” This interest in his immediate surroundings continued in Chicago, where he turned to the territorial gang graffiti he found in his own neighborhood northwest of Wrigley Field. Medina approached these images as an archivist and as someone familiar with power struggles, photographing several walls after gang members had swung cans of white paint at them to efface a rival gang’s graffiti. He eventually gained the trust of members of several Latino gangs, who allowed him to take their portraits in front of their graffiti, in a further gesture of power and defiance.