Identity economics provides a framework to analyze economic outcomes by establishing people's identities--not just pecuniary incentives--as primary motivations for choice. The heart of the framework is social difference and norms. This paper engages the emerging economic research into sources of divisions and norms: individuals, families, schools, governments, and social movements. The task at hand is to further to develop the micro-foundations of identity, in order to build a socially framed understandings of human motivation that will yield more robust accounts of behavior and institutions and yet better predictions of the implications of policy.