A genre that posits a version of history where some crucial event or events happened differently to our own, causing history after that point to evolve separately to our own. There are two primary versions of alternate histories, although these are hardly anything likely sub-genres. The first is where the narrative takes place during the events that first diverge from our own; these essentially take an historically familiar period and we see characters taking part in the unfamiliar events. An example would be HarryTurtledove's WorldWar or AmericanCivilWar series. The second is set in sometime after the critical events, where the characters exist in a world different from our own as a result of their different past. An example would be PhilipKDick's TheManInTheHighCastle.