Epigraphs are like little appetizers to the great entrée of a story. They illuminate important aspects of the story, and they get us headed in the right direction.
No epigraph, but the author does include this super handy family tree!
Hm, a family tree, you say? Seems like "family" might be a pretty important concept in this novel.
But let's take a close look at this family tree. You'll notice it's not exactly a careful genealogical record. It's more of a story-style tree, one that you can imagine the narrator drawing on a paper napkin with her sisters over a bottle of wine. Names aren't all that important (who can remember all those names?). But family legends are. "The Conquistadores" are included, and so is "the great-great-grandfather who married a Swedish girl."
The chart gets a little hazy around all Papi's brothers and sisters (the "33 other known Garcías") and around the "hair-and-nails cousins." But that's not the point. This isn't an objective historical record; it's a self-portrait. This is how the García Girls see themselves. It's where they think they came from. And that makes it a pretty good introduction to their family drama, don't you think?