The 2002 edition of Purity and Danger contains a Preface in which Douglas recalls the circumstances of the book's original publication in 1966, recaps some of its main ideas, clarifies some points, and revises some of her earlier statements (especially about the Book of Leviticus). She places her book in the social and cultural context of the 1940s through the 1960s, explaining that it was part of an effort to combat racist prejudices toward “primitive” societies and religions. She recalls that the book's ideas about structure and control were at variance with the anti-authoritarian social atmosphere of the middle and late 1960s; at the same time, the book anticipated the ecological concerns of the 1970s and beyond. 

Also in the Preface, Douglas revises some of her earlier statements about the prohibitions in the Book of Leviticus. Notably, she puts forward the idea that the avoidance rules express the idea that it is abominable to harm the animals in question, not that they themselves are abominable. “The prohibitions of unclean animals are not based on abhorrence,” but are rather part of an “intellectual structure of rules that mirror God's covenant with his people” (xv).