Persons or corporations owning real property permit others to hire it and charge them for its use, the object of the owner being usually to derive an income or profit from the property. Out of the agreement between the parties grows the relationship of landlord and tenant. The landlord is the one letting the property, the other hiring it and agreeing to pay rent, being known as the tenant. The landlord is usually the owner of the property but not necessarily; he may himself be the tenant of the owner, letting the premises to his own sub-tenants.