The extraordinary beauty of the Finger Lakes region is well known to its residents and to the many tourists who explore it each year. What is not so well known is the region's unique geology. Its distinctive features are the results of a singular combination of structural units and forces that operated thousands of years ago, when successive advances of the Ice Age continental glaciers thrust their fronts against escarpments extending across their path and into pre-glacial valleys. How these escarpments affected the flow of ice and how the glacial invasions remodeled the entire region is the subject of O. D. von Engeln's classic study. Following a brief prologue on the region's pre-glacial history, the author discusses each of the region's characteristic features: what caused it, its nature, its relation to other phenomena of the region and, often, to other distinctive topographic phenomena throughout the world. His book is a valuable and accessible introduction to the region's geologic history and provides insights into geologic methodology-how a region gives evidence of its history, what possible explanations for a phenomenon exist for geologists, and how they choose among them. Natives of the Finger Lakes, newcomers, and tourists alike will finish this book with a greater appreciation of this geologically fascinating area and with renewed curiosity about the formative years of our planet.