Does the frontier experience make America exceptional? When Frederick Jackson Turner presented this idea in 1893 as the core of his now-famous thesis, he set in motion a debate that historians of the American West have contended with ever since. The concept of a frontier, a moving boundary that defined civilization and circumscribed the Wild West, was not new — though the idea that it made Americans unique was. Turner's paper is reprinted in its entirety, followed by articles by three "New Western" historians who bring the dialogue up to the present day by applying modern concerns to this long-standing issue. The last selection looks forward, asking what Turner's ideas mean for America as we head into the twenty-first century.