Wow. Home sick & did nothing all day but read this book but I consider it a day well spent. Absolutely amazing. It is sort of the gay "The Man in the High Castle"-- the author even mentions PKD as someone who doesn't exist in the new Hitler-free AU-- but "History" has more of a romantic arc and a lot of dry British humor. "Castle" is very much a novel set in California, whereas this one seems very English. Both brilliant but both very different ways of handling the classic time travel/AU theme that we live in the best of all possible worlds and you attempt to change fate at your own risk. 
 Fry's paperclip structure is absolutely brilliant, the way the last line of every chapter and the first line of the next are linked. Once you realize he's doing it, you still can't stop compulsively reading. Just an amazing book.