Years of Rice and Salt, by Kim Stanley Robinson, was a frustrating read. It's a compelling book, full of 'so wrong it's right' moments, and a very satisfying ending, but it is a slog.
So, if you've never heard of Years of Rice and Salt it's an alternate history novel tracing the six or seven hundred years development in the world once Europe has been completely wiped out by the Black Death instead of only mostly being wiped out. The great civilizations of the world go through revolutions of philosophy and technology that parallel but never recapitulate the events of our own history: Dar al-Islam recolonizes Europe and goes through what might be termed a cultural renaissance in the far-off Central Asian city of Samarkand. A wayward Chinese military fleet discovers North and South America but the colonization and exploitation of the New World proceeds much more fitfully. The Industrial Revolution occurs in Southwestern India in the Travancori states.
As a fan of alternate history, I would say Robinson makes two interesting but risky choices in presenting his tale. The first is in telling the entire history from start to finish. If you are familiar with alternate history tales such as "Man from High Castle" by PDK, you may have grown used to having an alternate history set in an alter-present that mentions the events of the past without dwelling on them. Years of Rice and Salt dwells. It inhabits. It sets up shop, throws out an awing and stays awhile. By the final chapters of the book, Robinson is referring to the cultural reactions to previous fictional philosophical movements in locations and countries that don't exist in our world. I found this part pretty compelling actually, but you don't get there before first hearing an awful lot about Widow's Kang's theory of Cultural Collisions.
An obvious problem with this approach is how to knit together a coherent narrative. In Cryptonomicon, Neal Stephenson used the device of two generations of families separated by many decades, the struggles of the earlier generation informed the world of the subsequent. Robinson tells his story through the device of a jati, a group of reincarnated souls that pass in and out of each other's lives. There are something like seven reoccurring characters, each one adhering to a naming convention centering around the first letter of the character's name. There is a fiery, impatient revolutionary character ('K'), a placid and patient nurturer character ('B') and a thoughtful observer, ('S'). There's also 'S,' but he's never developed much beyond just being a bit of a jerk. Actually all of these characters are pretty thin and the conflict of their lives, while hinted at, never really comes together. Ultimately we follow these characters because we want to see what outrageous violence Robinson inflicts on the proper course of history.
Which gets to the second risky choice. This one occurred to me late in the book, when the history of Years of Rice and Salt began to finally diverge significantly from our own world. In "A Man from a High Castle," the change to history is an active one. Nazi Germany and Imperial Japan defeat the allies. America is now a divided, humbled nation. Something has been done to the world of the characters. In Years of Rice and Salt, the change is an absence. Western Civilization no longer exists but the rest of the world proceeds along pretty much as normal for a good third of the book. Robinson, I believe, recognizes this approach by naming the first part of the book "Awake to Emptiness." The changes to this alternate history are ones centering around what's missing, not what is present. So, ultimately Years of Rice and Salt begins by describing things identical to our history and it's only over time that the slow differences accumulate. The final effect is really powerful but, man, it takes a while to get there.