At the instigation of an anthropology teacher, I read this book when I was about 19 and found it shattering and profound. Now, however, returning to it years later (and having read in the meantime dozens of books on anthropology and anthropological issues, and having thought for years about what I thought I learned in this book) I'm not so sure it's as perceptive as I thought. In other words, I think what I may have found mind-blowing in my younger years was the insights of anthropology itself -- not so much the contributions of Ms. Douglas.
Having said that, there are four or five extremely interesting observations herein that will help explain, or at least clarify, some puzzling issues: why gangs "jump" initiates, why Muslims do not permit nonbelievers to enter Mecca, why frats "haze" their new recruits, etc., although you pretty much have to fill in those blanks for yourself: Ms. Douglas does not explicitly extend her theories to cover such aspects of modern society. I used to think the book was deep; now, I think (in general) that she doesn't go far enough with her theories, instead stopping short just when things are getting interesting.
Another unfortunate aspect of this book is that the author felt it necessary, in the first few chapters, to refute previous, erroneous ideas about filth and pollution. Unfortunately, many of the theories she refers to are complicated and difficult to follow, at least before you read the rest of the book. In other words, I think she should have left that section for last, instead just launching into her conclusions directly.