Jack Matthews has not only published more than 15 books of fiction, he taught classes in fiction writing to students at Ohio U. for over 4 decades. This book (which he distributed to students) consists of his teachings, insights, ramblings and ruminations about the art of fiction.
Many writing books include a chapter or two listing literary cliches to avoid. For the most part, Writebook doesn't do that. Instead it goes deeper and analyzes why some metaphors succeed and others do not. The funny Parable of the Indifferent Ear provides a good case study about how linguistic inventiveness doesn't always translate into effective writing.
Writebook touches upon some practical aspects of writing fiction (such as naming characters and writing speech cues). But Writebook focuses on helping the writer write more boldly and with more attention to the linguistic vehicles of thought. For Matthews, most stories fail through under-invention, not because the rules of narrative have been disregarded.