The basic physical element of realty is land. And surface rights are the basic legal rights related to ownership of land. They are the rights to occupy the surface of a land parcel. Mineral rights are the rights to dig or mine the earth beneath the surface which is also a part of the realty. The right to air space is the ownership of the air space above the surface of the land (for instance, if the branch of a neighbour’s tree grows into your air space f your right to air space would be violated and you would have the right to compel its removal). And water rights are the control of the water on the surface or under the ground« but because water flows across and under land，the owner’s control is not as absolute as his control of surface rights，mineral rights and air space.

Owners of realty do not all have the same ownership powers. For example, some owners cannot will away their ownership. Ownership powers are determined by the estate in land that a new owner receives. The major freehold estates are fee simple absolute conditional estates，life estates and future interests. Leasehold estates include estates at sufferance 9 estates at will，periodic estates and estates for years.

A fee simple absolute estate is an estate with all the ownership powers. The owner of the estate exercises all the power allowed by law, so there can be no other estate in the same land. Most buyers of homes, farmland and commercial property purchase the fee simple absolute estate.

A conditional estate makes ownership conditional on some act or event. For instance, A, the owner of a fee simple absolute estate, may sell and convey the estate to B，"only as long as no garage is built on the premises". In this example, if a garage is built，ownership would revert back to A. The buyer, B, owns a conditional estate.

A life estate is ownership for a time limited by the length of a human life. So the owner exercises all the ownership powers except the right to convey permanent ownership.

A future interest estate grants the owner possession of the realty when a life or conditional estate terminates.

When the owner of a freehold estate transfers to another the right to temporarily possess the realty, the landlord-tenant relationship is formed. The temporary transfer of the right of possession is referred to as demising or leasing the property. Since the transfer of possession is temporary, the owner of the freehold will eventually regain possession. This right to regain possession is called the right of reversion. The owner of the freehold is called the landlord or lessor, and the party receiving the temporary right of possession is called the tenant or lessee. After transfer, the tenant is said to own a leasehold estate.

There are four kinds of leasehold estates, with different rights attached.

Estate at Sufferance: It arises when one rightfully takes possession of property as a lessee，but then remains in possession after termination of the lease. In most states, a notice of termination is required for the landlords to evict an estate at sufferance.

Estate at Will ： When one takes possession of the realty with the landlord^ consent, but without entering into an oral or written lease, he owns an estate at will. The land-lord-tenant relationship can be terminated at any time by either party. Some states protect the lessee by requiring notice before eviction.

Periodic Estate ： this relationship arises when the parties agree on the terms and conditions of lease, but do not specify its length. Generally, this estate continues for the length of the payment period and is automatically renewed unless one party gives adequate notice of termination5. The main characteristic of the periodic lease is its flexibility. Since either the landlord or tenant can terminate, in most instances with a 30-day notice, the terms of the tease are open to easy revision.

Estate for Years ： When the parties agree on the beginning date and ending date for the lease, estate for years arises. Neither the landlord nor the tenant may terminate the lease without cause before the agreed termination date.

Frequently, tenants remain in possession after termination of the estate(holdover). When this occurs, the landlord generally has a choice of several remedies. The landlord can evict the tenant by asking the sheriff to force the tenant to remove from the property. Further, the tenant is liable for reasonable rent for the holdover period.

Answer the following questions :
1. What are the components of realty?
2. Do the owners of realty have the same ownership powers? What is the factor that determines the ownership powers of realty?
3. What are the differences between freehold estates and leasehold estates?
4. What is a conditional estate?
5. What is the right of reversion?
6. Give examples to illustrate the legal characteristics of a future interest.
7. What is a demise? List the rights and duties of the two parties of a demise.
8. When does an eviction occur and why is it important to the landlord?
9. Please compare the legal characteristics of different types of leasehold estates.
10. When a lessee holds over, how can the lessor get compensation?

The origin of American law regarding interests in real property is derived from English feudal rule dating back to the Norman Conquest in 1066. Under feudalism* the king owned all the real estate and conferred status on his favored knights by investing them with estates i they, in turn, would entrust estates to loyal subjects. The estate holders owed a variety of obligations to their land grantor, including military service and rents. Today, in the United States, land is held privately and the feudal hierarchy no long exists.