What book that hasn't been adapted into a TV show or movie do you think deserves an adaptation?

Dresden files not popular among these parts or how come nobody's mentioned it yet?

It has technically already been adapted, but it was a stupid procedural cop show with a twist rather than what it should be. If you want a more formulaic thing, just copy Amazon's Reacher.

Plus, since it's an urban fantasy, it should be cheaper to make than most other fantasy/sci-fi shows, I think.