A short orientation. Everything you need before you start — nothing you don't.
The world drowned. It took a long time.
That is the first thing to understand, because most people picture a wave. The sea rose for two hundred years before anyone called it an age. Coastal defences failed, then failed more often, then stopped being rebuilt. Towns were abandoned in the ordinary way — by insurance, by supply lines, by people leaving one at a time. If you have ever watched an institution fail slowly while everyone inside it behaves reasonably, you already understand the first fifty years.
Where people live
On the surface, in vessels and floating settlements that range from a few lashed hulls to towns of thousands. This is where most people are, and it is not romantic — a settlement is a machine for keeping several thousand people in fresh water. On the high ground, which is scarce, crowded, and almost always governed by whoever was standing on it first. And in the deep, in habitations built and maintained under pressure — the newest way to live, and the least forgiving.
What is a gyre?
A great slow circulation of water — a permanent, mapped current system. Gyres matter because they are the only large-scale thing in the ocean that stays put. Predictable water gives you predictable passage, which gives you somewhere to build. When people in these books say gyre, they mean something closer to a country than a current.
What is the field?
Here is where a shorter guide would lie to you, so this one won't. There is something in the drowned world that can be measured, listened to, and — under some conditions — answered. It is not a god. It is not a mind in any sense you would recognise. It is not on anyone's side. The people living with it do not agree about what it is, and the books never rule between them. You are not missing a chapter. Nobody in the world has the answer either.
Seven centuries, briefly
Dates follow the record where the record survives; the four centuries between the Second Drowning and Gyre Year 0 are the silence the later books inherit.
There were two drownings
The first was the world changing beyond anyone's control. The second, centuries later, was people trying to change it back on purpose — an engineering project, honestly meant and built by people who were good at their jobs. It went wrong, and a very large number of people died because a small number of reasonable decisions had been taken in the correct order.
What came out of it was not a ban on machinery but a rule about it, ten words long:
No machine anyone aboard cannot open, trace, and account for.
Centuries later nobody says the words any more. The rule is still there, buried inside the oath of an engineering order and the habits of a dozen trades, doing its work without a name. What institutions keep, what they quietly drop, and what they go on obeying long after they have forgotten why, is one of the things this saga is about.
What it is like to live there
Ordinary, mostly. That is the texture these books are after. Life runs on watches rather than days. Fresh water is the real currency. The work is trades work — pressure, pumps, rope, hulls, charts, physic, records — and most of it is inherited. Children swim before they walk properly. Everybody counts everybody at the companionway, twice a day, without being asked.
For the full picture — the institutions, the vocabulary, the timeline, and the record itself — see the companion volumes.