Adam Smith

"The rent of the land, therefore, considered as the price paid for the use of the land, is naturally a monopoly price. It is not at all proportioned to what the landlord may have laid out upon the improvement of the land, or to what he can afford to take; but to what the farmer can afford to give. "

"As soon as the land of any country has all become private property, the landlords, like all other men, love to reap where they never sowed, and demand a rent even for its natural produce."

"[the landlord leaves the worker] with the smallest share with which the tenant can content himself without being a loser, and the landlord seldom means to leave him any more."

"The landlord demands a rent even for unimproved land, and the supposed interest or profit upon the expense of improvement is generally an addition to this original rent. Those improvements, besides, are not always made by the stock of the landlord, but sometimes by that of the tenant. When the lease comes to be renewed, however, the landlord commonly demands the same augmentation of rent as if they had been all made by his own. "

"RENT, considered as the price paid for the use of land, is naturally the highest which the tenant can afford to pay in the actual circumstances. In adjusting the lease, the landlord endeavours to leave him no greater share of the produce than what is sufficient to keep up the stock"

"[Landlords] are the only one of the three orders whose revenue costs them neither labour nor care, but comes to them, as it were, of its own accord, and independent of any plan or project of their own. That indolence, which is the natural effect of the ease and security of their situation, renders them too often, not only ignorant, but incapable of that application of mind"

"[Kelp] was never augmented by human industry. The landlord, however, whose estate is bounded by a kelp shore of this kind, demands a rent for it"

"every improvement in the circumstances of the society tends... to raise the real rent of land."

Chapter 11, The Wealth of Nations