The rapid success of the _Political Economy_ showed that the public wanted, and were prepared for such a book. Published early in 1848, an edition of a thousand copies was sold in less than a year. Another similar edition was published in the spring of 1849; and a third, of 1250 copies, early in 1852. It was, from the first, continually cited and referred to as an authority, because it was not a book merely of abstract science, but also of application, and treated Political Economy not as a thing by itself, but as a fragment of a greater whole; a branch of Social Philosophy, so interlinked with all the other branches, that its conclusions, even in its own peculiar province, are only true conditionally, subject to interference and counteraction from causes not directly within its scope: while to the character of a practical guide it has no pretension, apart from other classes of considerations. Political Economy, in truth, has never pretended to give advice to mankind with no lights but its own; though people who knew nothing but political economy (and therefore knew that ill) have taken upon themselves to advise, and could only do so by such lights as they had. But the numerous sentimental enemies of political economy, and its still more numerous interested enemies in sentimental guise, have been very successful in gaining belief for this among other unmerited imputations against it, and the _Principles_ having, in spite of the freedom of many of its opinions, become for the present the most popular treatise on the subject, has helped to disarm the enemies of so important a study. The amount of its worth as an exposition of the science, and the value of the different applications which it suggests, others of course must judge.