Real estate law is the name given to the branch of civil law that covers rights to possess, use, and enjoy land and the permanent manmade additions attached to it. This includes the capacity to hold interests in real property, permissible interests in real property, relations between owners, relations between owners and the community, landlord and tenant relations, the transfer of interests in real property, and real property financing, including deeds and mortgages. Real estate transactions, such as purchases, sales, and leases, are governed by a wide body of federal and state law, and the requirements established by state law often differ from state to state.