The book has six parts: the five every era book of the series shares, and one of its own. Part I, Caeldon in the Medieval Era, shows the world at a glance: its two halves and the one crossing between them, a year as people live it, and the roads, rivers, and borders a traveller meets. Part II, Medieval Peoples and Powers, describes the civilizations of the era, who holds power in them and how, the faiths in practice, and magic as ordinary people meet it, with the awe and fear it still draws. Part III, Sickness and Remedy, tells what people suffer and how they are nursed: the common ills, poisons, and plagues, and the unnatural afflictions of magic, curses, strange places, and the Dark Entities. Parts IV and V are the atlas, one for each half of the world: The Cradle-Web, with its forests, mountains, deeps, river basins, and sealed places, and The Far Side, with its folds, scarps, coasts, and waters. Part VI, The Making of the Medieval Present, tells how the present came to be, from the Corridor Ages to the Wake-Seal, and gathers the era’s quarrels by theme for writers.

A writer with a region in mind can start at its atlas chapter and read outward. A writer who wants the whole era can read Part I, which is written as an overview, and follow whatever catches. Where something belongs to every era rather than this one, a chapter says what it means here and points onward; the reference names the chapter and the book it is in, as in Stewards and Resonants (FND), and the HTML edition links straight to it. Foundations also explains the voices of the series, the epigraphs and their in-world sources, the At a Glance boxes, and the Tensions (see How to Read This Book, FND). The beasts and crops of the era, and the stranger beings, are in A Bestiary of Caeldon.

A reference into another book of the series names the chapter or section it points to and adds, in brackets, that book’s short form after the link: (FND). The short forms are:

Every atlas chapter carries passages from Orrin Talloway, A Road-Book of Both Halves, set apart in italic within the section of the place they cross. He was a Human toll-clerk of the Serathic League in the Lower Serath, who rode the roads of the cradle-web, crossed the Glassbelt once each way with an Edgeway kindred circuit, arriving at the Lastwater Wells, was entered at the Turnwater Quays as a line under an escort, and, home again after some five years, wrote both halves down around 1,350 CR. No Human caravan or settler crosses the desert; Orrin was the exception. The road-book is arranged by region, as any road-book is, not in the order he travelled, so each atlas chapter carries the passages for its own country; they can be read on their own or as part of the chapter around them. Orrin writes with a clerk’s eye for tolls and tallies and a traveller’s nerves for raiders, ruins, and the dark, and like every voice in the book, the road-book is an edition-only voice, not part of the world’s canon.

Years are counted from one fixed epoch: BR, Before Reckoning, backwards into the deep past, and CR, Common Reckoning, forwards from it. A date marked c. is an estimate. The Medieval Era runs roughly from c. 500 to c. 1,500 CR, and this book describes its present, around 1,350 CR. Older dates in it, such as the Corridor Ages or the Settlement, are given as spans, plain windows of time rather than years anyone wrote down.

At the back of the book, A Short Chronology gives the three ages that made the medieval present, from the Corridor Ages to the Medieval Present itself, with their main events; the full chronology of all nine ages is in Foundations. A glossary explains the names and terms this book uses, and an index shows where each is told.