One of our most common terms, “identity” is rarely defined. In everyday language, its most common usages—“personal identity” and “social identity”—designate meanings not only distinct from one another but also hierarchically related. Personal identity is often assumed to mediate between social identities and make sense of them. Whereas our social identities shift throughout the day, what allows us to move coherently from one to another is often imagined to be our personal identity, or “who we are”—our constant. Personal identity conventionally arbitrates taste and lifestyle. “It’s just not me,” a potential home buyer says to her realtor. “That’s so you,” a helpful friend appraises as the shopper steps out of the dressing room. An “identity crisis” is a _crisis_ rather than an “identity opportunity” because personal identity demands proper and unimpeded expression. It is a value, something we prize. This sense of identity implies an immutable essence unchanged by physical development or external circumstances. The _Oxford English Dictionary_ dates the origins of this usage to the late sixteenth century, but it has recently been challenged by social theory and postmodern conceptions of subjectivity, and feminist theory has generated especially rich rethinkings of our notions of identity. In reference to social...