What the world would be like if some great event in history had never taken place or had taken a different course? A different decision made or the untimely death of someone else? Two thousand years ago the Roman writer Livy asked what would have happened if Alexander the Great had gone Westward to attach the young Roman Republic, instead of Eastward to conquer Persia. Last century Winston Churchill imagined Lee winning at Gettysburg, and wondered what the world would have been like. Now we have asked our writers to join together to bring new and exciting tales of these alternative worlds.