Two themes of special focus in the book are: Impurity and Sacrality. While they are often understood as being opposed to each other, the book examines how they are treated as two sides of the same coin, when it comes to menstruation. This is especially true in Indic traditions and pre-Christian polytheistic traditions like Greco-Roman, Mesopotamian and Egyptian. Impurity and Sacrality complement each other to form a comprehensive worldview in these cultures.