With our access to Google Maps, Global Positioning Systems, and Atlases that cover all regions and terrains and tell us precisely how to get from one place to another, we tend to forget there was ever a time when the world was unknown and uncharted--a mystery waiting to be solved.

In On the Edge, Roger McCoy tells the captivating--and often harrowing--story of the 400 year effort to map North America's Coasts. Much of the book is based on the narratives of mariners who sought a passage through the continent to Asia and produced maps as a byproduct of their journeys. These...