The complete Prior Signal argument in one book: the pattern, the case files, and a field guide you can actually run.
Around the year 500, a man stood on the engineered stone floor of a Roman granary and drove a wooden post into it. He wasn't mourning a fallen civilization. He was building a hall, on some good flat ground, in the only world he had ever known. The skills that made the floor beneath his feet had been gone for longer than anyone could remember — and he had no way of knowing that anything was missing.
This book is about how that happens. Not the fires and the invasions — the quiet part: how pottery, coinage, writing, and entire trades stop being economically possible and vanish within a working lifetime, while everyone inside the system experiences it as an ordinary year. It follows the pattern through Roman Britain, Bronze Age Greece, the Maya lowlands, and the Indus Valley — then into the present, where the same mechanism has already operated twice inside living memory, inside the best-documented institutions on Earth.
It ends with the thing none of the collapse literature gives you: a test. Ten signals, three questions, and one number to check — so you can audit any capability, ancient or current, yourself.
There is a way for a civilization to end that involves no fire, no invasion, and no single bad year. The lights stay on. The harvests come in. And underneath all of it, quietly, over the span of one working lifetime, the things that hold the world together stop being done — not banned, not destroyed, simply no longer worth the cost of doing — until one morning a man stands on an engineered Roman floor, driving a wooden post into stone he could not quarry, beside walls he could not raise, in the only world he has ever known.
He is not grieving. He has nothing to compare his world to. That is what the end looks like from the inside, and it is the reason this book exists.