Photo by Corrynn Cochran.

Florence Williams is a decorated environmental writer, one of my personal heroes (we launched our careers at the same ragtag Western environmental mag), and author of the new book Breasts: A Natural and Unnatural History. I caught up with her over a cup of coffee this week and learned a little about the biological theories of bustiness, the chemical cocktails that are showing up in breast milk, and a smartphone app that makes my childhood days of sneaking peeks at Playboy bunnies look positively pedestrian.

Q. Why write a book about breasts?