Eliminate economic rent—unearned revenue from having the monopoly on any piece (or many pieces) of land—and probably end houselessness, too, if paired with a resident's dividend, by taxing 100% of the annualized value of land that comes from surrounding community improvements (but do not tax the part of the value that comes from improvements made on the land).
The reviewer summarizes the book thusly:
Poverty and wealth disparity appear to be perversely linked with progress, The Rent is Too Damn High, and it's all because of land.
Henry George himself puts it pretty succinctly:
Rent, in short, is the share in the wealth produced which the exclusive right to the use of natural capabilities gives to the owner.
This economic rent share of wealth, as opposed to interest on investment or wages for labor, is completely unearned.
That there is no moral justification to collecting this sort of pure rent is not the concern— it is the inevitable result that is the concern:
Though neither wages nor interest anywhere increase as material progress goes on, yet the invariable accompaniment and mark of material progress is the increase of rent – the rise of land values.
So that ultimately,
where the value of land is highest, civilization exhibits the greatest luxury side by side with the most piteous destitution
And the solution to ill effects of the use of the land monopoly to extract economic rents from society is to tax land at as close to 100% of the portion of revenue coming from its unimproved value— the money someone would pay to use that land in the given societal context regardless of what is built on the land. This value should be given to each person in the community equally, what George calls a Citizen's Dividend but which we, conscious of the gatekeeping around citizenship in the 21st century, call a Resident's Dividend.
As the reviewer, Lars A. Doucet, notes, "the value of the land has its origin in the productive labors of the entire community, so it's a simple act of justice to give the returns to those who actually produced the value, which is society at large."
