There is no more striking difference to be found between a primitive and a highly developed legal system, than in the relative importance of the law of contracts. In modern times the central subject of the whole body of the law is that of contracts. In the study of law the first branch of the substantive law to be taken up is that of contracts, and this subject and its subdivisions occupy a large part of the entire course. Our highly developed and specialized economic and industrial systems render a multitude of contracts a necessity to business life, and the importance of the subject is daily increasing.

In the early systems the law of contract is practically limited to that of bailments and executed sales. The simple conditions and the primitive state of society give no occasion for the creation of complicated or future contracts. The important rights of the individual are those natural and absolute rights which belong to him as a member of the community, rather than those special ones which he acquires by contract.