Final answer:
Portions of the most important decisions each year in the context of an increased number of courts and cases were compiled in year books, contributing to the body of common law.
Step-by-step explanation:
As the number of courts and cases increased, portions of the most important decisions of each year were compiled in year books. The concept of common law, or case law, is crucial in understanding this compilation. Common law—also known as precedent—is developed by judges through the decisions of courts.
It evolves case by case as judges make rulings that are then respected and applied by future courts. Stare decisis, a vital principle within common law, dictates that cases with similar facts should be decided in the same way, respecting the consistency of precedent.
This ensures certainty and stability in law, contributing to the legitimacy of the court system. Important compilations like Blackstone's Commentaries on the Laws of England contributed significantly to this body of law by organizing and making it accessible for legal professionals and scholars. The correct option is (e) year books.