Flow aims to tell the "cultural story" of menstruation and, for the most part, it hits the high points. The book starts out with a long discussion, ironically enough, about why people don't talk about it. Nowhere do they mention the most obvious reason: because it's pretty icky. Another big chunk of the book has to do with advertisements. They reproduce ads for what they dub "femcare" through out the book that span the last century and the author's deconstruction of the ads was the best part of the book. It's amazing what ad writers could say without actually saying anything.
This deconstruction also leads into their other major point, that companies are medicalizing what are, essentially, natural processes. Some of the products that were sold even as recently as the 1970s that were dangerous, like super absorbent tampons that caused toxic shock syndrome or Lysol douches that lead to an increase in infections. A lot of these ads, when they used words, preyed on women's fears and embarrassments and gaps in our knowledge. Interesting and horrifying all at the same time.
I think when I picked up this book I was expecting a Mary Roach-caliber book. While I have no doubt that the authors did extensive research, I wish it were easier to trace their sources. A lot of their examples of bad medical sciences were glossed over and summarized to the point where it was hard to see what studies they were talking about. Further, instead of Roach's intellectually curious tone, the authors of Flow were a little too obvious about being matter of fact. So, instead of being matter of fact, they actually wrote after some paragraphs stating a common belief or an alarming study, they'd actually write something like "Or did they?" or "But is it really?" It was like having the author's constantly winking at you or having a conversation with a particularly pushy pair of aunts with no boundaries.
But, did I learn anything? Yeah, a few things. Mostly, I learned about the fine art of advertising. I really enjoyed all the reproduced ads. And I learned what women used before "femcare" and, boy, do I pity my grandmother and my female ancestors. Flow was a very interesting read.