From the preface by Charles H. Kerr, the translator, when this book was first published in 1908: On the tenth of March, 1896, the same year that the last despairing revolt of the small producer against capitalism in America was to end in the overwhelming defeat of Bryan, an Italian scholar published in the city of Rome the remarkable work which is now for the first time offered to American readers. To publish this book in America at that time would have been an impossibility. The American socialist movement was then hardly more than an association of immigrants who had brought their socialism with them from Europe. Today it numbers at least half a million adherents, and its platform is an embodiment of the ideas first adequately stated in the Communist Manifesto of 1848, and now first adequately explained and elaborated in this remarkable work of Labriola. The central and fundamental proposition of socialism is not any scheme for reconstructing society, on a cut-and-dried programme, nor again is it any particular mathematical formula showing to what extent the laborer is robbed by the present system of the fruits of his labor; it is precisely this Historical Materialism, which Labriola has so admirably explained in the present work.