Man's relations to land are of two major types: land use and land tenure. The first refers to the use made of land in supplying human needs; the latter includes the relations among men, determining their rights and responsibilities in land.' Legal aspects of land tenure are concerned with the laws of property in agricultural land. The law of property may be found in constitutional provisions, statutes, court decisions, common law, or local custom. The laws governing land tenure, whether they concern the State or the individual, the owner or the tenant, the trustee or the mortgagee, or the heir or the squatter, are laws of property, concerned with the distribution of rights in land. Any adjustment in our system of agricultural land tenure represents an adjustment in the position of agricultural land as property. For example, a rural zoning ordinance always changes the rights of the holder of a piece of land; an easement for an electrical transmission line divides rights in land between the owner and the public utility company; and the Kansas law requiring that the landlord compensate the tenant for certain unexhausted improvements under specified conditions reduces the landlord's rights in the land. The tenurial relationships established among men are social phenomena and are never static; they are ever changing. In fact, man's economic, social, political, and religious history is replete with terrific and sustained struggles for a better and better distribution of the rights and responsibilities in land. These struggles have always had as their objective the readaptation of the manmade tenure system to the needs of the time. The battle, of necessity, has been terrific because of the reluctance of those in power to yield to change, and has been sustained owing to the slowness with which significant changes in fundamental arrangements are made even after the need has been recognized. But during the centuries the struggle has been carried on against the power of vested interests and in spite of the costliness of what are inevitably trial and error methods and the dead weight of cumbersome legal traditions. During the major part of our national life, however, owing to our preferred economic position and to numerous programs giving opportunities to or pacifying the disadvantaged, adjustments in our system of land tenure have been exceedingly few and we have tended to fall behind in light of the many new problems facing us.