What do you think "the Catcher in the Rye" was really about?

After reading the The Catcher in the Rye again, I was wondering what other people thought the message of the novel was. This idea of Holden as "the Catcher in the Rye" is open for a lot of interpretation. It's such a famous and thought provoking book, and I have some different views on the book, then I've read. What do you think Salinger was really writing about?