Making History — Stephen Fry

This “terrific” novel of alternate history asks: What if Hitler had never been born? (The Washington Post)
 
Michael Young is a graduate student at Cambridge who is completing his dissertation on the early life of Adolf Hitler. Leo Zuckermann is an aging German physicist haunted by the Holocaust. Together, they idealistically embark on an experiment to change the course of history. And with their success is launched a brave new world that is in some ways better than ours -- but in most ways even worse.