This is a scanned copy of a book published in the early 20th century which presents pedigree charts based upon court cases argued during the medieval period. This version is more complete and less expensive than the General Books LLC edition, which doesn't include the pedigrees derived from Bracton's Notebook or the index. The print is occasionally faded but readable.
The material is of great value to genealogists working with medieval English families. Because the pedigrees are based upon legal proceedings, one might expect them to be more reliable than charts in the various Visitations, though not all families found in Visitations are represented here. However, even for families which do appear in Visitations, you may find references to family members in the Plea Rolls who aren't shown in Visitations.
A very useful reference and highly recommended.