The zipper is one of those inventions—along with the bicycle—that seems as though it should have occurred much earlier in history. How complicated could it be to assemble two wheels, two pedals, and a chain? Or to align two jagged strips of metal teeth and shuffle them together? There is no complicated chemistry here, no harnessing of invisible wavelengths. And yet the modern bicycle didn’t appear until the late 1800s, and the zipper didn’t really become the zipper until 1917 (when it was patented by a Swedish immigrant in Hoboken). The precision necessary to craft a working bicycle chain or a smoothly meshing zipper was simply beyond us for all those prior millennia.