Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Somber, Hopeful, Matter-of-fact
It sounds like it's all over the map, but the book really does embrace all three notions. Jack's life is far from cheerful and we feel every savage punch that life sends his way. What can we say? "I blubbered again in bed that night" (3.11) says "unhappy" about as clearly as anyone could wish for.
At the same time, we see how he copes by adopting a more hopeful stance, either by changing the present through his process of self-reinvention, or looking towards a brighter tomorrow that even he suspects will never come true:
It was burning bright for me when Chuck and I left Seattle and started the long drive home. (31.15)
How does he marry the yin of a tough life to the yang or wild hopes and dreams? By ruthlessly sticking to the truth. Wolff is very good about using his current grown-up perspective to show us the flaws in his spry young teenage thinking. He never sugar coats anything, but he also doesn't play the poor-little-me card when talking about the bad things that happened to him. Even when things are at their most emotional, like when Dwight stalked his mother and "tried to strangle her in the lobby of our apartment building," (31.6), he doesn't embellish. That just-the-facts-ma'am approach lets him marry to seemingly separate tones into one mighty autobiographical package.