Sexologists introduced the idea of gender in 1955 to describe the biological attributes, sexual characteristics and social roles that characterize a person as male or female. Subsequently, however, the idea of gender came to take on larger political, social, sexual and intellectual meanings. Following the social movements of the 1960s, all forms of identity -- including biological sex and identities linked to human sexuality -- have come to be understood as expressing relationships of power, often generating new political activisms, identity formations and gender identities that go well beyond both biological sex and the conviction that there are only two genders. Beginning with activist theories associated with feminism and the emergence of "women's studies" as an academic field, this course highlights critical perspectives on how gender informs our thinking about ourselves, our knowledge of the world around us, and our own intellectual work.