William the Conqueror wished to know the details of the land he had conquered, England. He let his knights and barons have big areas of land, and wanted rent money from them. The Domesday Book was a record of every farm, village and house so that he knew how much rent he should get. Only some small villages in the countryside are not in the book. Major cities like London and Winchester are also not in the Domesday Book, perhaps because of their size, or because (not owning land), the people could not be taxed. 