Introduction: The “Great Unknown”

It has been 150 years since John Wesley Powell’s famous voyage down the Green and Colorado rivers, yet he is still an icon. Why? The answer to that question, as this volume makes clear, depends upon whom you ask. Some would say it is because Powell was the first person to run the Grand Canyon’s world-class rapids. Others might mention that he made the US Geological Survey into a modern, effective agency. Still others would point to Powell’s groundbreaking ideas on water and land policy, or his prodigious work in ethnology and anthropology. A few academics might recognize that he