I have a hard time writing five star reviews; it can be hard to avoid gushing and to say something that hasn't already been said. But this book deserves the effort, so here goes.
As others have recounted, The Seamstress is about the lives of two Brazilian sisters in the early twentieth century. They're raised together in the highlands of the state of Pernambuco, but early in the book each departs on her separate journey: the younger sister, Luzia, is taken by a group of bandits that happens through the town, leaving the older, Emilia, alone and forced to make a hasty marriage in order to fulfill her dream of living in the city. Chapters alternate between the two for the rest of the book. I found them equally interesting, and they provide an excellent contrast: Emilia lives in the city, and observes its progress and the making of history firsthand, while Luzia remains in the countryside, acquainting readers with its harsh landscape and traditional lifestyle. The thematic implications here are obvious, and the settings are beautifully drawn. I know some reviewers have complained that the book is too long, but the plot is only part of it: without the little character-illuminating moments and the descriptions so vivid I felt as if I was there, this book wouldn't be nearly as good as it is.
The development of the main characters was excellent. I had sympathy for both of the sisters from the very beginning, and found them interesting throughout despite their making some rather difficult decisions. Luzia's development in particular was fascinating: I could tell early on that her story was not going to be romanticized as the girl-kidnapped-by-outlaws usually is, but was still surprised at the (inevitable, in retrospect) direction that it took. Emilia seems to be the more difficult character to like for many readers: she's more conventional, struggling against the traditional roles of women in high society, even while she loves fashion and dressmaking. In some places the author uses major political events and drama to liven up her chapters. But ultimately (and perhaps surprisingly given her character at the beginning of the book) I found her the more admirable of the two.
The flip side is that, while the most important supporting characters in each narrative are also well-developed, the more secondary and minor characters seemed a bit flat, including those who shouldn't have been given the amount of page time they received (Lindalva, Ponta Fina). Still, I loved the nuances of the relationships between the characters. And while writing style, as long as it's competent, is not my first priority in choosing what to read, I can say that the prose quality here is excellent.
The only thing I didn't much like about this book is its divergence from history: for instance, it seems fairly obvious that Celestino Gomes is meant to represent Getulio Vargas, but why change the names at all? It reminded me of Isabel Allende's work in that respect (and a comparison to Allende is a huge compliment, even if refusing to include the real names of historical figures does annoy me in both cases). Also, there's no excuse for not including a glossary at the end of the book; Portuguese words pepper the text, and while most can be understood from context, it's standard practice to include translations and pronounciation help for readers unfamiliar with the language.
Ultimately, I both fully enjoyed and was impressed by this book--an excellent combination. I recommend it to aficionados of both historical and literary fiction.