Henry George's proposal to abolish all taxation except a tax on the value of land, so that the community recovers land rent while labour and capital go untaxed.
In more detail
In Progress and Poverty (1879) George argued that it is not necessary to confiscate land, only to confiscate rent. Because land is fixed in supply, a land-value tax cannot be shifted by reducing supply and does not discourage production, and it would push speculatively held land into use. Single-tax enclaves such as Fairhope, Alabama, tested the idea locally. Critics doubt that land rent alone could fund a modern state and point to the difficulty of valuing land separately from buildings.