Breakthroughs, in my opinion, isn't so good because of its combat, but rather for how it handles the war's effects upon the peoples of different lands. It covers all these facets of daily life, from the women factory workers, to the blacks, the socialists, and even the foreigners who slowly adapt to American rule. Turtledove really does this well by having one or two characters from each area of life, save the US military, covering all the different aspects of life as well as all parts of the American Front. I personally enjoyed the perspective of a certain Lucien Galtier, who, as the story progresses, goes from a person who takes pride in being a Frenchman, a Canadian, to someone who learns that Americans aren't all the devils they're made out to be, and eventually makes peace with the fact that perhaps things were going to be different from now on. This book, and the ones previous to it, really show the people's struggles to adapt and survive in these war conditions, which is something that this series does better than its competitors, and makes Breakthroughs, and to an extent A Walk In Hell, a good book.