An encounter with Aaron Siskind inspired American photographer Alan Cohen (born 1943) to abandon his doctoral program in thermodynamics and instead pursue a career in photography under Siskind's tutelage. For the past two decades Cohen has traveled the world, using the medium of black-and-white photography to record places marked by the political acts or the covert actions of others; places marked by time through the course of natural and often catastrophic occurrences. Crumbling stone walls and other near-invisible demarcations of political boundaries are among the mute witnesses he chooses as his subjects. "I have come to understand that history, in a contemporary image, can be sited," Cohen writes. "Events can--and do--become geography." This book tracks the evolution of Cohen's work over a 40-year career, reflecting the artist's belief in photography as both a social document and a meditative art.