Repeat photography has proven to be a valuable, reliable and accessible methodology for evaluating and illustrating changes in landscapes over time. Ecologists often use the techniques as a complimentary tool for quantative research, providing a historical context for current findings, while historical images are a key source of information for historians. Written by an ecologist and a historian, both of whom have lived in the town of Banff for decades, The Lens of Time brings together these two perspectives. The photographs in the book span a period from the 1870s to the present decade; the majority are presented in pairs (more or less) the same view to permit comparison.