Despite Covid-19 posing largely the same problem everywhere, nations reacted quite differently. Three main approaches were taken: some clamped down on the infected, imposing targeted quarantines, others shut down across the board, still others did much less, sometimes little at all. The science of how Covid spread was uniform the world over, so that did not explain such divergence. Nor did the political nature of the countries under attack, since both democracies and autocracies could be found implementing the same strategies. Nor did how nations had approached pandemics in the past. The introduction lays out the general themes of the book.