"Portage Paths: The Keys of the Continent" by Archer Butler Hulbert is a historical account written in the early 20th century. The text focuses on the significance of portage paths as vital routes in American history that facilitated exploration and communication across the continent. It explores these pathways from the perspectives of explorers, missionaries, and traders, highlighting their strategic importance in geographical and historical contexts. The opening of the work introduces the concept of portage paths as the "Backbone of America," inviting readers to imagine a journey across the continent from the Atlantic to the Mississippi Basin. It describes the challenges faced by early travelers, specifically the "voyageurs," as they navigated these routes while carrying canoes and supplies. The text emphasizes how these paths, often found in rugged terrains, were crucial for connecting waterways and enabling human movement during the early days of exploration, while also hinting at the profound historical implications of these routes in shaping America's development. (This is an automatically generated summary.)