In the second half of the book, to me there is more emphasis on the true identity of the Garcia girls. In the last part of the book, they are not the hybrid, dual-cultured, Americanized women that we know; they are 100% pure Dominican children, living a Dominican life. We see that identity is dynamic, that it has changed over time. Although they will never be completely American, at one point in time they have been completely Dominican. And although they feel later on in time that they no longer belong in the Dominican Republic, in childhood it was their whole identity. This feeling of completeness is reflected in the childhood stories. They are happy, innocent stories. The underlying ominousness of the political danger is not scary for them, since they do not grasp its full meaning. When they were children, they never questioned who they were or where they belonged, and this made for a generally happy childhood, with gifts and adventures and a big family and lots of wealth and support.
The fact that the story is told more or less backwards by Alvarez makes the understanding of the story an incremental process. With each chapter we know more and more about the past, and therefore understand more clearly the events in the "present". It is only at the end that we understand clearly the circumstances surrounding the Garcia de la Torre family's escape from the Dominican, and this clarifies very much the events that happen later on (timewise) in the story.
This novel definitely emphasizes the importance of family, of blood ties the support network that they provide. Although there will always be conflict between family members - misunderstanding, anger, resentment, difference of opinion - in the end, the family is the most important thing, and the only thing you can depend upon. This is a very Latinamerican way of seeing life.