A decent generalist history of the Comanches and, well, their rise and fall. The book presents a meandering mix of historical developments and personal stories from the frontier. The history part is fairly straight forward and serviceably written, and is mostly just a recounting of the events that occurred. The personal histories were occasionally interesting, but I felt like they often confused the historical progression more than they enlightened. I almost would have preferred two books or two different sections; one the history and one the extended anecdote. The book is fairly brutal and un-PC, and does describe several dozen of the more notable atrocities.
While the book wasn't that great overall, Empire of the Summer Moon did have several points that raised it to a solid 3 stars. One is that much of the book is set in Central Texas, and it was neat to read the history of the place where you grew up. A second reason is that the tactics of plains warfare were interesting, and how in some ways the plains really did mirror the "ocean" of grass that it was compared to. Horses were as necessary as ships were in the ocean, and to be deprived your horse could easily mean death by exposure and deprivation. Similarly, the Comanches never focused on taking or holding a fort or hill, in the same way that navies wouldn't care about a few square miles of ocean. Speed was the best defense, and everything was about scouting, setting up advantageous engagements, and protecting your own population centers while threatening your enemy's. Actually, it reminds me more of the start of the Culture-Iridan war than anything else, if the Culture had had more Reaver in them. Although I guess the Reavers were partially based off the Comanche, so that is a bit circular. Anyway.
Finally, I enjoyed the book as a corroboration of the theories laid out in Diamond's _Guns, Germs, and Steel_. The sort of same-lattitude technology transfers that Diamond emphasized about took place here, where the horses bred in Arabia were transferred and flourished on the Texas Plains. This led to the ascent of the Comanche, as they fully adapted their formerly marginal society to the new technology. They became mini-Mongols who were able to dominate a huge swathe of the mid-continent, and hold off enormous hordes of settlers for decades. It's interesting to think about what the Comanches could have become, if they hadn't received the technology 1000 years after the Eurasians did.
P.S. They have several pictures of various settler families. Jesus they were a tough and angry looking bunch. If the question is "How many high plains five year olds I could take in a fight?", I think the answer is 1? maybe 2?