The Mappa Mundi, arguably the most famous of all medieval world maps, is now displayed in Hereford Cathedral. This book was commissioned to mark the map's display in a newly-built museum, and the map is here seen in context with other detailed maps of the 12th to the 14th centuries; at that period these were a peculiarly English genre, on which recent discoveries have thrown new light. The map's origins are examined, as well as the sources for its geographical outlines, and for the wealth of information it provides. This account, intended for a general audience, is of one of the most revealing artefacts surviving from the 13th century. The book includes new photography of the map itself.