Guest One Line, the other Guest is correct up to a point, BUT -- if you happen to be using the rather common device of starting off each chapter with an apropros quote, no matter how small, courts in the US have disallowed this as "fair use" -- because, narrowly speaking, it doesn't come under the umbrella of educational, scholarly, or review purposes. I know published writers whose editors have nixed their cute chapter-heading blurbs just on the grounds that clearing the rights can be an absolute nightmare and they didn't even want to try.
-Glenn