Domesday Book is the main source for an understanding of late Anglo-Saxon England and the Norman Conquest. And yet, despite over two centuries of study, no consensus has emerged as to its purpose. David Roffe proposes a radically new interpretation of England's oldest and most precious public record. He argues that historians have signally failed to produce a satisfactory account of the source because they have conflated two essentially unrelated processes, the production of Domesday Book itself and the Domesday inquest from the records of which it was compiled. New dating evidence is adduced to demonstrate that Domesday Book cannot have been started much before 1088, and old sources are reassessed to suggest that it was compiled by Rannulf Flambard in the aftermath of the revolt against William Rufus in the same year. Domesday Book was a land register drawn up by one of the greatest (and most hated) medieval administrators for administrative purposes. The Domesday inquest, by contrast, was commissioned by William the Conqueror in 1085 and was an enterprise of a different order. Following the threat of invasion from Denmark in that year it addressed the deficiencies in the national system of taxation and defence, and its findings formed the basis for a renegotiation of assessment to the geld and knight service. This study provides novel insights into the inquest as a principal vehicle of communication between the crown and the free communities over which it exercised sovereignty, and will challenge received notions of kingship in the eleventh century and beyond.