A more thorough explanation:

The liber ruber scaccarii was an ancient register of the names of those holding land per baroniam during the reign of Henry II. It is also known as the Red Book of the Exchequer.

One example of the liber ruber scaccarii is the record of William de Warenne, who held land in Sussex and Surrey during the reign of Henry II. Another example is the record of Robert de Beaumont, who held land in Leicestershire and Warwickshire.

These examples illustrate how the liber ruber scaccarii was used to keep track of who held land per baroniam during a specific time period. It was an important document for the administration of the Exchequer, which was responsible for collecting taxes and other revenues for the Crown.