...or, at least, one Australian bookseller's take on it.
Follow the link below to access a frank report on sales of SF, fantasy, paranormal fiction and horror (including a dedicated 'bestselling zombie titles' list!) at Dymocks Southland over the past year, posted by NecroScope's own Keeper of the Dead.
http://chuckmck1.livejournal.com/35428.html
