Consider the following excerpt from Chapter 1 and pay attention to the information Salinger chooses to have Holden reveal about himself in the book's first pages.
I mean I've left schools and places I didn't even know I was leaving them. I hate that. I don't care if it's a sad good-bye or a bad goodbye, but when I leave a place I like to know I'm leaving it. If you don't, you feel even worse.
Why did Salinger decide to have his narrator state his feelings about goodbyes at this early point -- before, in fact, we even know Holden's name?