All wealth consists of desirable things; that is, things which satisfy human wants directly or indirectly: but not all desirable things are reckoned as wealth.

The hope that poverty and ignorance may gradually be extinguished derives indeed much support from the steady progress of the working classes during the 19th century.

Producer's Surplus is a convenient name for the genus of which the rent of land is the leading species.

Capital is that part of wealth which is devoted to obtaining further wealth.

All wealth consists of desirable things; that is, things which satisfy human wants directly or indirectly: but not all desirable things are reckoned as wealth.

I admit that these terms and the diagrams connected with them repel some readers, and fill others with the vain imagination that they have mastered difficult economics problems, when really they have done little more than learn the language in which parts of those problems can be expressed, and the machinery by which they can be handled. When the actual conditions of particular problems have not been studied, such knowledge is little better than a derrick for sinking oil-wells erected where there are no oil-bearing strata.

Knowledge is our most powerful engine of production.