An assignment (Latin cessio) is a term used with similar meanings in the law of contracts and in the law of real estate. In both instances, it encompasses the transfer of rights held by one party—the assignor—to another party—the assignee. The legal nature of the assignment determines some additional rights and liabilities that accompany the act.

Assignor remains liable unless there is an agreement to the contrary. An agreement must manifest intent to transfer rights, it may not necessarily be in writing, words will do, and the rights assigned must be certain. The effect of a valid assignment is to extinguish privity between the assignor and the obligor and create privity between the obligor and the assignee.

Assignment of rights under a contract is the complete transfer of the rights to receive the benefits accruing to one of the parties to that contract. For example, if Party A contracts with Party B to sell Party A's car to Party B for $10, Party A can later assign the benefits of the contract - i.e., the right to be paid $10 - to Party C. In this scenario, Party A is the obligee/assignor, Party B is an obligor, and Party C is the assignee. Such an assignment may be donative (essentially given as a gift), or it may be contractually exchanged for consideration. It is important to note, however, that Party C is not a third party beneficiary, because the contract itself was not made for the purpose of benefitting Party C. However an Assignment only transfers the rights/benefits to a new owner. The obligations remain with the previous owner. Compare Novation.

The Law is a system of rules and guidelines which are enforced through social institutions to govern behavior. Laws are made by governments, specifically by their legislatures. The formation of laws themselves may be influenced by a constitution (written or unwritten) and the rights encoded therein. The law shapes politics, economics and society in countless ways and serves as a social mediator of relations between people.

A general distinction can be made between civil law jurisdictions (including Canon and Socialist law), in which the legislature or other central body codifies and consolidates their laws and common law systems (including Sharia), where judge-made binding precedents are accepted. In some countries, religion may inform the law; for example, in jurisdictions that practice Islamic law, Jewish law or Canon law.

The adjudication of the law is generally divided into two main areas. Criminal law deals with conduct that is designated dishonest by the government and in which the guilty party may be imprisioned or fined. Civil law (not to be confused with civil law jurisdictions above) deals with disputes between individuals or organizations, in which compensation may be awarded to the wronged litigant.