The Great Unspoken

What's the great unmentionable in human society? Sex, nah. Death, nah. These are both talked about everywhere. We just pretend they're not.
The great unmentionable is defecation, and its companion, urination. Okay, the second of those two occasionally gets a mention in public life, but the first is mostly viewed as something no one actually does.
Why am talking about this then? Because I've just seen a review of a book called The Big Necessity: The Unmentionable World of Human Waste and Why It Matters. It's written by Rose George, and was published by Metropolitan Books, back in October this year.
More than 6 billion people have to deal with this (an anagram of shit, did you realise?) day in and day out, and in many parts of the world there just isn't the provision for it, which is why there's a great deal of disease, and so many deaths from diarrhea (I'm using the US spelling because I can never remember the English one.) According to the review (which is based on the book's stats), diarrhea kills a child every 15 seconds. Can this really be true? Perhaps it can, but it's certainly hard to comprehend.
The review, by Bill McKibben, on the Books & Culture site, is well worth reading (only a couple of pages.) It makes a book on a not-so-enticing subject enticing!