The Man in the High Castle by Philip K. Dick

 It's a standard trope of alt-history to imagine what might have happened if the Nazis had won the second world war. In this book, the point of divergence is that Franklin D Roosevelt was assassinated in 1933 leading to the Great Depression lasting for longer and ensuring the US remained isolated and ill prepared for war while the Nazis consolidated their hold on Europe. Eventually the Axis powers turned their attention to America with the Nazis conquering the east coast while Imperial Japan took the west, leaving a neutral buffer zone in the Rocky Mountain states. By 1962 the former Axis powers find themselves in an uneasy Cold War with the political situation in Germany uncertain.

Most of this book takes place in San Francisco under Japanese control, with an antique shop owner called Robert Childan selling relics of American history to curious Japanese settlers and a bigwig called Tagomi who wants something to impress an important visiting trade partner. A recently fired metal worker called Frank Frink (hiding his Jewish identity) starts a jewellery business hoping to sell to the same market. Meanwhile Frank's ex-wife Juliana who teaches judo in Canon City, Colorado starts a relationship with a sleazy Italian truck driver who clearly has bad motives. There are Nazi spies at work and events will shake the fragile detente between Japan and Germany.

What really surprised me about this book was the role of the I Ching, where yarrow sticks are scattered randomly to tell the future. Most of the characters use it at critical points for guidance and insight, and its significance only becomes clear at the very end of the book. Another twist is the presence of the book The Grasshopper Lies Heavy, banned in most places, with the radical idea that the Nazi victory had not been inevitable and describing a very different outcome to the war. However, this is not a description of our world, but yet another possible timeline where President Rexford Tugwell wisely anticipated the attack on Pearl Harbor and moved the fleet before it could be destroyed. 

The style of the book is clipped and economical, and Dick seems to have been influenced by Japanese poetry with references to waka and haiku forms. There's not a huge amount of plot to write home about, but it's an eerie piece of scene setting with the world as portrayed seeming very plausible. The use of the I Ching also hints at events being pre-destined with alternative choices perhaps branching to different time lines that can somehow be glimpsed. The ending of the book is ambiguous and open ended, and apparently although Dick had planned a sequel he couldn't face getting back into the heads of Nazis like Heydrich again.