I think the 'meaning' of any book is just what influenced the reader or how it made the reader feel. An author can write a book with a certain 'meaning' in mind but the readers might interpret the 'meaning' deferently.
For example:
The author could write the following sentance: Johnny killed Bob and then went to jail.
The auther's 'meaning' in writing that sentance: Killing is bad.
Reader #1's 'meaning' after reading the sentance(am I spelling that right?): COOL!!!
Reader #2's: I'm sure he had a good reason.
Reader #3's: Obviously he didn't do a good job of hiding the evidence.
I know, that is a terrible example. But I'm sure you get my point. A story can have many 'real meanings' to it. Am I way of track with the 'meaning' to this question???