The Cassandra scene in Aeschylus' Agamemnon occupies over 250 lines, yet scholars and critics, preoccupied with such large issues as the changing conception of justice in the Oresteia and the male/female and Chthonic/Olympian conflicts, have tended to give it relatively little attention. In a sense this is understandable: the scene in no way Advances the action of the drama, and critics who have learned from Aristotle that the ‘plot’ is the ‘soul’ of a tragedy might well feel that it is unnecessary to bother about a scene which could be omitted with no effect on the movement of the story. Nevertheless, it is difficult to believe that Aeschylus would have inserted so long and unexpected a scene in his play, just at the point when the audience would expect Agamemnon to be murdered, if it did not have an important dramatic purpose. Furthermore, in actual performance, Cassandra frequently rivets our attention more than any other character; on stage her scene can be the most gripping and affecting part of the play. In this essay I shall try to account for the powerful effect that the Cassandra scene has on the audience; then I shall discuss its place and function in the Agamemnon and the trilogy as a whole.