Domesday Book is largely about landowners and their estates, both before and after 1066. It represents Anglo-Saxon and Norman landholding in very different terms. The nature and terminology of landholding in 1086 is relatively straight-forward. Domesday Book has been called a 'blueprint for a feudal society', an observation prompted by a structure which represents landed society after the Conquest as based strictly upon tenure: tenants-in-chief held their fiefs from the Crown, tenants held manors from tenants-in-chief, and the occasional subtenant held his manor from the tenant immediately above him on the feudal ladder. Every man had his lord, and his lord was the man from whom he held his land, very probably the lord who had granted him that land within living memory. It was a structure of great simplicity, and for a generation or two bore some relationship, if distant at times, to the real world.
The nature and terminology of Anglo-Saxon landholding, on the other hand, are less easy to grasp and were expressed in a bewildering variety of formulae. In essence, Anglo-Saxon lordship was based upon personal bonds rather than land tenure, though tenure did enter into some relationships. The predominance of personal ties was simply a reflection of the fact that Anglo-Saxon landed society had deep roots. Most landowners would have inherited their estates, and few probably knew how their ancestors came by them. Lordship - a legal requirement on all men - was therefore a matter of choice, a bond of commendation forged from self interest: lords needed men to serve them, men needed patronage and protection. Anglo-Saxon lordship was of the bastard feudal variety into which Anglo-Norman society would quickly evolve.
In these circumstances, the wholesale disinheritance of the English landed classes after the Conquest was bound to give rise to disputes over title. A Norman granted the estates of one Anglo-Saxon magnate was tempted to treat the estates of that magnate's men as part of the grant. Others might claim the estates of the same men on different grounds - that they were dependencies of manors owned by another Anglo-Saxon magnate, for instance. There were practical reasons, therefore, for collecting data on Anglo-Saxon landholding in 1086; but the complexity, variety, and inconsistency of what was collected showed that the commissioners struggled with this task and in some circuitsabandoned the attempt entirely.
For more detail, see Sir Fredrick Pollock and F.W. Maitland, The history of English law before the time of Edward I (second edition, 1898); Susan Reynolds, Fiefs and vassals: the medieval evidence reinterpreted (1994); and Judith A. Green, The aristocracy of Norman England (1997).