At the time, I thought of it this way: it was as if bacteria that used to cause deadly plagues, but had long been considered conquered by modem medicine, had reemerged in a form resistant to all the standard antibiotics. Here's what I wrote in the introduction to the first edition: "So far only a limited number of people have actually fallen prey to the newly incurable strains; but even those of us who have so far been lucky would be foolish not to seek new cures, new prophylactic regimens, whatever it takes, lest we tum out to be the next victims."