I have a very strange relationship with this novel, and more specifically, its author. L. Neil Smith is probably one of the most recognizable libertarian scifi authors around. I personally find libertarianism ridiculously naive, and since the majority of Smith's books deal with libertarian themes, I have a hard time taking them seriously or enjoying them.
The Crystal Empire, however, is not one of those. It is an alternate history novel, pure and simple. As another reviewer said, if there was a libertarian message in this one, I missed it. Thankfully.
The plot deals with the adventures of Sedrich Sedrichson, a native of a small Vinland-ish settlement in eastern North America - one of the last remnants of European culture in this world, founded by people fleeing a Black Plague that almost completely decimated Europe. Sedrich has been tasked with delivering the daughter of the Caliph of the Saracen-Jewish Empire, which dominates most of Europe, to her future husband, the god-like emperor of a strange and amazing Sino-Aztec empire in the far west of America.
Sedrich is a pretty sympathetic character, as is Ayesha, the Caliph's daughter. Their interaction, their chemistry, is great, and their story is evocative of the best of classic literature. If Shakespeare collaborated on an alternate history novel with George RR Martin, this might be the result. Yes, it's that good, in my opinion.
So... an author whose works and personal philosophy I find idiotic has managed to turn out what is probably my favorite alternate history novel, one which I re-read every couple of years. Very odd. At any rate, if anyone out there has been turned off of Smith after his Probability Broach universe novels, I urge you to give this one a try, and possibly Henry Martyn, also by Smith, which is fairly decent as well.