Literacy research has focused on how reading and writing are shaped by traditions and conventions, those discussing issues of identity, whether about gender or race or social class or other perspectives, have argued that our identities are constructed and performed in response to the cultural environments we inhabit. Identity is a shifting contingent thing, negotiated and regulated depending on the social context, both performance and socialization. The social construction of identity gives it a central role in issues of power and ideology. The difference between oppression and opportunity in a given context results from how the identity is performed by us and interpreted by others. This chapter focuses on agency as a core concept because of its connection to social and cognitive sciences as well as education. In addition, agency implies the possibility of action and decision. The chapter presents an overview of key concepts discussed in the subsequent chapters of this book.