PREFACE. It is remarked by another author, that * he who is fully master of the subject of Value is already a good political economist.” ¢ Even for its own sake,” he adds, * the subject is a matter of curious speculation: but in relation to Political Economy it is all in all: for most of the errors (and, what is much worse than errors, most of the perplexity) prevailing in this science take their rise from this source*.” Although much has been written and many efforts have been made fo overcome the ob- stacles, which present themselves in this part of economical science, it may be affirmed with little risk of contradiction, that the success has not been in proportion to the labour be- stowed. There appears to have been too little circumspection at the outset. The ground- work of the subject has not been examined * The Templars’ Dialogues on Political Economy, in the London Magazine for April, 1824, pages 341 and 342.