The subtitle of this book (by Peter Turchi) is "The Writer as Cartographer," so it's basically an extended metaphor taking what we know of and can learn from maps and applying that to the writing process. I'm enjoying the book a lot (understandably, as it combines two great loves I have: maps and writing). It's not a book of immediately applicable, concrete things to do with writing, but more a meditation almost, an exploration of the theme through a handful of more specific attributes of mapping that allows (requires, even) you to draw a lot of the implications for writing yourself. Even when it draws the connection more explicitly, it leaves the specifics of what exactly that means up to you, which is challenging but good in my opinion.
Anyway, here's the quote, in a section introduced by discussing how north-as-up is a convention so strong to many of us that seeing a map oriented differently can seem not just strange but wrong. Yet it is merely convention, something useful but not any more reflective of the world than any other choice someone might make. In the same way, writing rules and techniques can be conventions, useful for orienting ourselves but not inherently definitive:
But simply discovering them isn't enough. We need to devote ourselves to the ongoing practice of questioning the rules we have found most useful (including those we hear ourselves offering as advice) and the fundamental assumptions of our work, constantly checking for empty routine, throughtless employment.