Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Desperate, Reflective, Hopeful
Since Crispin's our narrator, and he's telling a story about himself, we learn a lot about how Crispin is feeling about what's happening to him through his tone. Early in the book, Crispin's tone is desperate. He feels that everyone he ever relied on has deserted him—his mother, Father Quinel, and even God. Look at how he describes his discovery of Father Quinel's body:
Stifling a shriek, I knelt down, my whole body shaking. Terrified, I made a short and desperate prayer to Saint Giles, imploring his blessings on the priest and on myself. That done, I ran away.
God, I was certain, had completely abandoned me. (11.26-27)
Any time you see "imploring" in the mix, the tone is probably desperate. But once Crispin's no longer in immediate danger, he has time to process what's happened to him, and he spends much of his time on the road with Bear reflecting on the events of his life, how his life has changed, and what this all means for his future:
Bear had to be wrong. Yet I found myself thinking it was not so bad to have fallen in with him. To be sure, he was a rough-and-ready man. The things he said confused me. Even his calling me by the name Crispin was unsettling.
Still, if Bear fed me and protected me, I might, at least, survive a little while. In any case I had little choice. God had willed it.
And yet—thinking on what he said—I asked myself if I were to live by questions, what questions would they be? About my father? And those things Father Quinel had said about my mother—if they be true or not. And maybe—I allowed—I'd ask what was to be my fate. (24.63-65)
No longer feeling completely lost and alone, here we see Crispin reflecting, trying to wrap his mind around Bear and what he's told him and make some sense of his current situation. And by the end, Crispin moves onto hope about his future. You know, because he actually believes he has one:
And by the ever-loving God who sits above, my heart was full of more joy than I had ever felt before. I was unfettered, alive to an earth I hardly knew but was eager to explore. What's more, I knew that feeling to be my newfound soul, a soul that lived in freedom. And my name—I knew with all my heart—was Crispin. (58.46)
Sometimes the tone in a book stays pretty much the same throughout, but in this case, as Crispin's lot improves in life, his tone cheers up as well.