This book changed my life. Borderlands: La Frontera, The New Mestiza by Gloria Anzaldua. The borderland referenced is this book is more than just one of geographical space, it is one of identity or language and struggling to survive while living in a place that is neither here nor there. While Anzaldua speaks/write personally from the physical/internal Chicana borderland, as a Puerto Rican woman born on the NY side of the island, this book made me cry. From the chapter How to Tame a Wild Tongue:

Linguistic Terrorism
Deslenguadas. Somos los del espanol deficiente. We are your linguistic nightmare, your linguistic aberration, your linguistic mestisaje, the subject of your burla. Because we speak with tongues of fire we are culturally crucified. Racially, culturally, and linguistically somos herfanos-we speak an orphan tongue.

With the current discussion on immigration and assimilation (or perceived lack of), this book is a seminal work on the politics of mestizaje. Using Mexican/Chicana metaphors, written in poetry and prose, English and Spanish, the book itself is a metaphor and lives on the borderland.

You can buy this book here.