It's only a week since Walls of Men went live, but already my mind is turning to the next writing project. This is because writing is what I do to unwind, and without it I get really bored. I'm trying to fill the empty hours with chores and watching vintage TV and movies, but that's only a stopgap.
Sooner or later, I'll take on a new project.
I'm thinking it will be fiction. Long Live Death was actually very easy to write (took 6 weeks or so) and while post-publication corrections were a headache, they were also a function of my desire to see it in print ASAP because of its applicability to the political situation.
Walls of Men, on the other hand, was really complicated and stressful. Add in the fact that both books didn't really provide the escape from reality that fiction writing does.
On the plus side, non-fiction doesn't take the same creative energy - you set your thesis, do research and write what you find. No dead-end plots or unconvincing characters. You have to describe a world rather than create one.
Inspiration is also important. This is why have never written a "fantasy" book in the style of J.R.R. Tolkien - I don't know what I would say that needs saying. I've got at least half a dozen story ideas in the genre, but none rise above the level of Dungeons and Dragons-grade fan fiction.
I'm sure in time, this will work itself out and in the meantime I'll see what I can draw from my viewing.