For those of you who never read the book and were curious about the title, or those who read it a long time ago and forgot, here's the passage behind it:

'Anyway, I keep picturing all these little kids playing some game in this big field of rye and all. Thousands of little kids, and nobody's around - nobody big, I mean - except me. and I'm standing on the edge of some crazy cliff. What I have to do, I have to catch everybody if they start to go over the cliff - I mean if they're running and they don't look where they're going I have to come out from somewhere and catch them. That's all I'd do all day. I'd just be the catcher in the rye. I know it; I know it's crazy, but that's the only thing I'd really like to be. I know it's crazy.'
-Holden Caulfield