Domesday Book ( DOOMZ-day) – the Middle English spelling of "Doomsday Book" – is a manuscript record of the "Great Survey" of much of England and parts of Wales completed in 1086 at the behest of King William I, known as William the Conqueror. The manuscript was originally known by the Latin name Liber de Wintonia, meaning "Book of Winchester", where it was originally kept in the royal treasury. The Anglo-Saxon Chronicle states that in 1085 the king sent his agents to survey every shire in England, to list his holdings and dues owed to him.

Written in Medieval Latin, it was highly abbreviated and included some vernacular native terms without Latin equivalents. The survey's main purpose was to record the annual value of every piece of landed property to its lord, and the resources in land, manpower, and livestock from which the value derived.

The name "Domesday Book" came into use in the 12th century. Richard FitzNeal wrote in the Dialogus de Scaccario (c. 1179) that the book was so called because its decisions were unalterable, like those of the Last Judgement, and its sentence could not be quashed.

The manuscript is held at The National Archives at Kew, London. Domesday was first printed in full in 1783; and in 2011 the Open Domesday site made the manuscript available online.

The book is an invaluable primary source for modern historians and historical economists. No survey approaching the scope and extent of Domesday Book was attempted again in Britain until the 1873 Return of Owners of Land (sometimes termed the "Modern Domesday") which presented the first complete, post-Domesday picture of the distribution of landed property in the United Kingdom.