It is remarkable how doctrines that have been refuted time and again can still be touted by reviewers as having merit today. If there is an unearned increment and if it could be isolated, it could be taxed without doing any damage. But it is simply not feasible in the vast majority of cases to determine what per cent, if any, of the current rent on a piece of land is unearned. Some is due to improvements and some to making a superior appraisal and thus setting it aside for a specific use. Only an omniscient being could succeed in a general sense in separating these contributors to the rent of a specific parcel of land. If one is really interested in taxing the unearned increment, he should advocate a tax on consumer surplus or on the positive externalities of technological advance. Nor is it more fair to tax owners of land than, say, to tax people who earn income because of their high IQs, natural beauty, or natural athletic skill. Davenport, Herbert J. "The Taxation of Unearned Increment,"Addresses and Proceedings of the National Conference on State and Local Taxation, November 1907. Davenport, H.(1910) "The Single Tax in the English Budget," Quarterly Journal of Economics, February, 1910. Davenport, H. J.(1911) "The Extent and the Significance of the Unearned Increment," American Economic Review 1: 322-332) Davenport, H.(1917), "Theoretical Issues in the Single Tax," American Economic Review 7 (March): 1-30. Wieser, Friedrich A. von.(1960) "The Theory of Urban Ground Rent." In Louise Sommer. (ed) Essays in European Economic Thought." London: D. Van Nostrand. (Originally published in German 1909) Pat Gunning