Coming-of-Age; Adventure; Young Adult Literature
If you've hung out in the "Symbols" section at all, then you won't be surprised to see that Doll Bones is a coming-of-age story. After all, it's all about three kids struggling to let go of their childhoods, and in the end, with one possessed doll six feet under, they finally succeed in doing so. We're not saying they're, like, forty year olds paying bills or anything, just that they definitely start out as kids and end up as young adults. To this end, the book is also young adult lit, though it leans toward the younger side of the genre since the main character is twelve.
As for the adventure bit, Zach, Alice, and Poppy sneak from their homes in the middle of the night to take a bus hours away. And before they reach their final destination, they have to escape shady characters, steal a boat, break into a library, and much more. If that doesn't count as adventure, then we honestly don't know what does.