I'm quite intrigued by his system of writing. It's nothing magical, he works on it hard and the process is roughly connecting various ideas together. He finds interesting ideas and write them down and then when the time is to go for a book, he tries to find ideas and concepts that work together. He then writes a rough outline of a book and then goes and fills in chapters after which he gets multiple reviews/revisions before it goes out.
Sounds almost like getting a rough requirements or ideas, then writing a more detailed specification and finally fully developed software that goes through rigorous testing and refinement.
It's quite different to how I thought most writers write. My assumption it's more straightforward with little preparation.