Focusing on ethnicity and its relation to conflict, this book goes beyond sterile debates about whether ethnic identities are ‘natural’ or ‘socially constructed’. Rather, ethnic identity takes different forms. Some ethnic boundaries are perceived by the actors themselves as natural, while others are perceived to be permeable. The argument is substantiated through a comparative analysis of ethnic identity formation and ethnic conflict among the Anywaa and the Nuer in the Gambella region of western Ethiopia. The Anywaa and the Nuer are not just two ethnic groups but two kinds of ethnic groups. Conflicts between the Anywaa and Nuer are explained with reference to three variables: varying modes of identity formation, competition over resources and differential incorporation into the state system.