Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Dark, Yet Humorous
In a book about necromancers, you better believe that death is going to make an appearance somewhere. Descriptions of mortality and violence show up a lot throughout the story and pack a huge punch in terms of setting a dark tone for the events.
Check out the scene where Sam has his first (forced) necromancy lesson with Douglas—the spirits Douglas raises to torture Sam all died "a violent death. Their throats were slashed, or they were sliced open like gutted fish" (19.167). Wow. Gross. There's also a lot of graphic descriptions of veins being opened and Douglas's dungeon being smeared with blood. Again, pretty disturbing stuff.
Surprisingly, though, a great deal of this book is also hilarious. Pitting themes of death and darkness against humor is a bit unusual, but the tension between the two only serves to engage us even more.
Probably the clearest example of this happens when Brooke's head arrives in the mail at Sam's apartment. We initially feel the shock and trauma of Sam receiving the package, but when Brooke opens her mouth and starts talking, the scene takes on a completely different tone. "Ow, cut it out you guys!" she exclaims. "Really Sam, you don't just drop somebody's head" (4.90). If you were laughing hysterically during this scene while simultaneously wondering if you should be laughing at all, you're not alone.