I have a question, I don't think this has been asked, and I did a search, although perhaps i didn't use the exact right words.
Now I haven't read any of the books, but I do know that all technology, including gun powder, electricity, IC engines, and steam power are rendered useless. Now I can understand eliminating most of that stuff, but steam power seems a bit difficult to work out, you would need to make such a drastic change to the fundamental laws of physics to quite possibly make the world unrecognizeable. Also I'm not entirely sure you really need to eliminate it in order to reduce society to mideival levels, since electricity is gone, you eliminate its use as a source of electricity, and acts solely as a form of propulsion. So my question is, how does this Stirling explain this in the books?