This biography examines the life and legacy of Frederick Jackson Turner. Best known for his 1893 essay "The Significance of the Frontier in American History" - the most enduring explanation of our national development - Turner was a leader in establishing the field of western American history and in shaping the broader history discipline. Placing Turner's ideas in the context both of his own times and of current historiography, Allan G. Bogue elucidates his far-reaching influence as thinker, scholar, mentor, and teacher. Weaving together accounts of Turner's personal and professional life, Bogue addresses intriguing questions: Why did Turner fail to produce that great work of substantive research on which he labored for more than half his career? And why have his ideas inspired so much debate and controversy, even to this day?