A wide-ranging journey through the history of borders and an exploration of their role in shaping our world today.

Since the earliest known marker denoting the edge of one land and the beginning of the next-a stone column inscribed with Sumerian cuneiform-borders have been imagined, mapped, moved, and fought over. In The Edge of the Plain, James Crawford skillfully blends history, travel writing, and reportage to trace these borderlines throughout history and across the globe.

The role of borders extends beyond specific sites of conflict. On the largest scale, borders define the limits of empire-the two walls in Britain that once represented the northwestern edge of the Roman Empire; the mythological eastern gate supposedly closed off by Alexander the Great; China's virtual "Great Firewall." On the smallest, human scale, cell walls are the last physical barrier against disease, after lines of quarantine have failed.

Borders are as old as human civilization, and focal points for today's colliding forces of nationalism, climate change, globalization, and mass migration. The Edge of the Plain illuminates these lines of separation past and present, how we define them-and how they define us.