In taking up the new edition of “The Nine-banded Armadillo; A Natural History,” I was still pondering over the news I had recently read explaining that Dasypus novemcinctus, the taxonomic binomial for the title species, has been discovered to be four different species, the northern most of which was to be re-identified as the Mexican Long-nosed Armadillo. How, I wondered, does one review a book about the natural history of a species when that species has since the time of the book’s publication been re-defined?