[Cross-posted from New Books in History]  Historically speaking, who you were depended on who your rulers were and the ethnic identity (including language, religion, and folkways) of "your" people. In the era of nation-states–that is, our era–these two characteristics have, for most people, been fused. Ethnic Germans live in Germany, ethnic Chinese live in China, ethnic Egyptians live in Egypt. The exceptions to this rule are two: ethnic minorities (e.g., Jews, Kurds, Uyghers, etc.) residing in nation-states and people who live in the shifting borderlands between nation-states.

Omar Valerio-Jiménez's fascinating book River of Hope: Forging Identity and Nation in the Rio Grande Borderlands (Duke University Press, 2013) is about identity in one particularly interesting shifting borderland, that found in the Rio Grande region between New Spain/Mexico and the United States. Valerio-Jiménez shows that the people of the Rio Grande were, ethnically speaking, many: a variety of native Americans, Spanish soldiers and colonists, Mexican and American immigrants of every stripe. The border shifted back and forth; the river and its people for the most part remained, adapting to new regimes and new conditions. Just "who" they were at any given time depended on a whole variety of factors, all of which are expertly explored by Valerio-Jiménez. Listen in to our fascinating discussion.