Caeldon did not begin as a story. It began as a question about how a world would work if its deepest law were not matter but resonance: if everything that exists were, at bottom, a frequency, and what makes a thing itself were the way it keeps on sounding. The answer turned out to need ten currents running through everything, planes stacked behind the visible world like overtones behind a note, and powers that people would come to call gods. It needed peoples shaped by those currents and by one another, and a past long enough for mountains to be worn down and rebuilt while the peoples forgot and remembered who had lived there before them. The whole of it, the world and the work of making it, came to be called the Decachord: ten strings, sounding together.

For a long time Caeldon lived only in working pages. There are registries of species and civilizations, regions and sites, religions and dated events. There is a timeline that runs from the first stirring of the cosmos, some thirty-five billion years before the reckoning of years began, to a medieval present around 1,350 CR. And there are hundreds of pages that argued with one another until they agreed: on which people crossed which river first, and on who keeps a ford and who only thinks they do. Those pages are still the ground the world stands on. They were built to be consulted, cross-checked, and corrected, and they are good at it. They were never meant to be read from end to end.

This book is.

The Chromatic Chord retells the same world in a voice meant for reading. It explains the cosmos and the gods as a natural philosopher would explain them to a curious student. It tells the deep past as a history book tells it, with spans of thousands of years and the few hard dates that history gets to keep. Each era it walks through as a traveller meets it: the fields and fords, the halls and feuds, the ruins on the hills and what still walks in them, the smell of a forge at a river crossing, and the small habits that tell a stranger which side of a border they have woken up on. Along the way it lets the world speak for itself, in the sayings, songs, and books its people make, because a place is known as much by what it says about itself as by what is true of it.

Nothing in it is new. Every fact in these chapters has a home in the technical pages, and the book only gathers, orders, and tells. The voices that open each chapter, the almanacs and chroniclers and poets, are the one exception: they belong to this book, and they speak in it so that the world has a voice and not only a description. Where this book and the technical pages disagree, the pages are right, and this book will be corrected.

The book is one of a series, and the series is built to grow. The world it describes changes from era to era, and so the series is divided the same way. What does not change, the cosmos, the powers, the laws of magic, the peoples as kinds, and the deep past, is told once, in this book, Foundations. Those laws are fixed: magic and the cosmos follow rules that never bend and can be relied on, however strange or terrible the things they make possible. Each era then follows as a book of its own, with its own picture of the world, its own peoples and powers, its own atlas, and its own account of how that present came to be. The first is The Medieval Era, an age of high fantasy: heroes and monsters, haunted ruins and the treasure in them, feuds fought with swords and magic that still draws a crowd. The eras after it grow more crafted as magic and making grow into one another, until the last of them reach the stars; the wonder stays, and so do the laws beneath it. The Industrial Era and the eras after it will join the series as books of their own as they are written, and the chapters already here will stay where they are. Beside them stands A Bestiary of Caeldon, for the beings of the world that are not peoples.

The title needs a word. A chord is notes sounded together. A chromatic chord reaches for the notes between the notes, the half-steps that a plain scale steps over, and the word is older than music: in Greek, chroma is colour. The technical pages give the world its notes: who lives where, since when, by whose sword or oath. This book is after the rest of it: how those notes sound together, the colour of the thing, and what lives in the intervals between one fact and the next. The Decachord is the world; The Chromatic Chord is the world heard in colour.

It is written for people who want to make something of their own in Caeldon: a novel or a short story, a campaign or a single evening’s game, a set of rules, a map, a song. What it can give them is the ground to stand on and the feel of the place. The stories are theirs.

The world is larger than any one telling of it. What follows is a way in.