The supplementary papers added contain, in briefest form, the aphorisms respecting principles of art-teaching of which the attention I gave to this subject during the continuance of my Professorship at Oxford confirms me in the earnest and contented re-assertion. JOHN RUSKIN, BRANTWOOD, _April 29th, 1880._ PREFACE TO THE 1857 EDITION. The greater part of the following treatise remains in the exact form in which it was read at Manchester; but the more familiar passages of it, which were trusted to extempore delivery, have been written with greater explicitness and fulness than I could give them in speaking; and a considerable number of notes are added, to explain the points which could not be sufficiently considered in the time I had at my disposal in the lecture room. Some apology may be thought due to the reader, for an endeavour to engage his attention on a subject of which no profound study seems compatible with the work in which I am usually employed. But profound study is not, in this case, necessary either to writer or readers, while accurate study, up to a certain point, is necessary for us all. Political economy means, in plain English, nothing more than "citizen's economy"; and its first principles ought, therefore, to be understood by all who mean to take the responsibility of citizens, as those of household economy by all who take the responsibility of householders. Nor are its first principles in the least obscure: they are, many of them, disagreeable in their practical requirements, and people in general pretend that they cannot understand, because they are unwilling to obey them: or rather, by habitual disobedience, destroy their capacity of understanding them. But there is not one of the really great principles of the science which is either obscure or disputable,--which might not be taught to a youth as soon as he can be trusted with an annual allowance, or to a young lady as soon as she is of age to be taken into counsel by the housekeeper. I might, with more appearance of justice, be blamed for thinking it necessary to enforce what everybody is supposed to know. But this fault will hardly be found with me, while the commercial events recorded daily in our journals, and still more the explanations attempted to be given of them, show that a large number of our so-called merchants are as ignorant of the nature of money as they are reckless, unjust, and unfortunate in its employment.