If you’re on social media, you’ve probably seen various small publishers pointing out that their books are available via Bookshop.org which appears to be an online ordering option for people who want to avoid the “giants” like Amazon, Book Depository and BarnesAndNoble.com
I haven’t ordered from them yet, but I’ll probably give it a try soon and see how it goes.
They seem to have lots of things listed, including my three currently in print books, The Human Alchemy, The Lure of Devouring Light and Hieroglyphs of Blood and Bone. See here:
https://bookshop.org/books?keywords=michael+griffin
I assume Armageddon House will appear at some point as well.