The title of the book Sokka is holding is 子白 “child white”
As far as I Know, and I’ve also asked people who know more than me, this is not the title of a real book, or a recognizable phrase. My best guess, unless one of you knows better, is an injoke.Someone suggested it to be random characters, but honestly ATLA has never done that before.
Oddly enough, though, when I googled the term, I got A LOT of cabbage pictures.








