This is a how-to-write book. However, it is not a beginning how-to-write book but an advanced one. Which makes it unique in my experience. Indeed, it's explicitly aimed for published novelists. . . fortunately for the size of his audience, unpublished writers can use the techniques, too, though they do assume a certain amount of writing competence.
It doesn't cover the basics. What it does cover is plot, character, theme, premise, setting, and other elements with an emphasis on what the big sellers do with them that differentiates them from books that sell rather less. Also information on the market.