What's an Epigraph??

So for the longest time, I never knew what an epigraph was! Obviously, I had seen quotes in the pages before some of the books that I have read, I just never knew that they had a specific name. Personaly, I actually really love epigraphs. I feel like the lead the reader to a certain frame of mind before they ever even begin to read the story. If the author is astute enough, and chooses a perfect quote to encapsulate the book that the reader is about to read it lends a whole new level to the book itself.

These are the books in which I found my favorite epigraphs of any others in my collection.

From "The Lost Symbol" by Dan Brown there is the epigraph: 

I actually haven't read the book, so I don't know if it encompasses the book or not. I do really like the quote though. 

From "The Jane Austen Book Club" by Karen Joy Fowler

First of all, it's Jane Austen. Second of all, this not only encompasses all of her writing, but it certainly encompasses this book. Yep. Just love it.

From "Old Magic" by Marianne Curley

This book is all about the links to the past, so this epigraph definitely goes well with the book. 

Those are my favorite epigraphs of the books that I own. ^_^ Do you have any epigraphs in books that you like? Have you read any of these books?