It's been the big question about this series since it first came about its popularity – what is the appeal of a series about economics? Even after this first volume, that particular question can't be entirely answered but it seems safe to say that the bright-eyed, fox-tailed naked girl may have something to do with it. While that isn't to say she's all Spice and Wolf has going for it, the series seems apt to push this fact more so than anything else.
Was Koume Keito always the illustrator of this series? He's a fairly (in)famous H-doujin artist (behind the well known "The Pollinic Girls Attack"), and I would've never associated him with a series like Spice and Wolf at all.