The binding legal principles established are: (1) The doctrine of res judicata applies where there has been a final and definitive judgment by a competent court, and the three essential elements are satisfied: same parties (or their privies), same subject matter, and same cause of action. (2) These requirements must be interpreted expansively in appropriate cases, particularly where prior judgments sound both in personam and in rem, to permit issue estoppel even where strictly different relief is sought, provided the same underlying question arises in both cases. (3) The requirement of 'same parties' does not require an exact line-up of litigants; the addition of disinterested officials or nominal parties does not defeat the plea. (4) Where the relief sought (such as a caveat) is anchored on an underlying right that has already been definitively determined by a court, res judicata will apply notwithstanding that different relief is now sought. (5) A judgment founded purely on adjectival/procedural law without determining the merits does not constitute a final and definitive judgment for res judicata purposes, but where courts have made substantive findings on parties' rights, those constitute final determinations that estop further litigation.