Our bodies are archives of sensory knowledge that shape how we understand the world. But if global environmental changes continue at their present unsettling pace, how will we make sense of time and place when the air, land, and water around us are no longer familiar? Joy Parr, one of Canada’s premier historians, tackles this question by exploring situations in the recent past when state-driven megaprojects such as chemical plants, dams, nuclear reactors, transportation corridors, and new regulatory regimes forced people to cope with radical transformations in their work and home environments. In each case, the familiar was transformed so thoroughly that residents no longer recognized where they lived or, by implication, who they were. Sensing Changes and its associated website, http://megaprojects.uwo.ca, make a key contribution to environmental history and the emerging field of sensory history. This study offers a timely, prescient perspective on how humans make sense of the world in the face of rapid environmental change.