The 'Common Law' legal system is derived from English legal tradition and relies on courts applying'custom' to resolve legal disputes. For detailed definitions and a history of the development of the common law in America and other former British colonies, see the sources below.
Contract law is that body of law dealing with "... oral or scripted agreements related to trade of commodities and services, properties and money. It also contains topics related to qualities of contractual duties, restriction of activities, liberty of contract, privacy of contract, conclusion of contract, and also contains agency relationships, business document, and deals of employment.
(Law Dictionary (Black's) Online- What is Contract Law?)
"Real property (realty) consists of land and objects that are permanently affixed to land, such as trees and buildings. Real property generally is immovable, whereas personal property (also known as personalty or chattel) consists of movable objects. Personal property can be tangible, such as a book or car, or intangible, such as an idea or the good will of a business. Property law largely consists of issues relating to real property, rather than to personal property. By and large, however, the rules are the same for both." (Real Property in a Nutshell / Bernhardt and Burkhart. Chapter 1. Real Property and Ownership)