In this commentary on Shakespeare's "Measure for Measure", Marc Shell focuses on the play's basic themes of sexual extremism, exchange and political order. At the crux of the play, he notes, the novice nun Isabella accuses her brother Claudio: "Is't not a kind of incest, to take life/From thine own sister's shame?". Shell's analysis shows how Claudio's request is a kind of incest in a reading that extends his earlier work on philosophical and literary economies. Developing fully the thematic role of the monastic orders in Shakespeare's drama, Shell demonstrates that the play lays bare some of Western culture's most fundamental tensions - between natural and political teleologies, between Christian and political ideals of brotherhood and the incest taboo, and between the pragmatic imperative to classify people and the moral imperative to treat them all alike.