In 1813, Saint-Simon published his _Mémoire sur la Science de l’Homme_, in which he laid down notions which were the germ of Auguste Comte’s _Law of the Three Stages_. With the peace which followed the Battle of Waterloo, a tremendous stimulus was given in France to industrial activity, and Saint-Simon formulated his motto “All by industry and all for industry.” Real power, he showed, lay not in the hands of governments or government agents, but with the industrial class. Society therefore should be organised in the manner most favourable to the working class. Ultimate economic and political power rests with them. These ideas he set forth in _L’Industrie_, 1817-18, _La Politique_, 1819, _L’Organisateur_, 1819-30, _Le Système industriel_, 1821-22, _Le Catéchisme des Industriels_, 1822-24. Since 1817 among his fellow- workers were now Augustin Thierry and young Auguste Comte, his secretary, the most important figure in the history of the first half of the century. Finding that exposition and reasoned demonstration of his ideas were not sufficient, Saint-Simon made appeal to sentiment by his _Appel aux Philanthropes_, a treatise on human brotherhood and solidarity. This he followed up in 1825 by his last book, published the year of his death, _Le Nouveau Christianisme_. This book endeavoured to outline a religion which should prove itself capable of reorganising society by inculcating the brotherhood of man in a more effective manner than that of the Christian Church. _Fraternité_ was the watchword he stressed, and he placed women on an equal political and social footing with men. He set forth the grave deficiencies of the Christian doctrines as proclaimed by Catholic and Protestant alike. Both are cursed by the sin of individualism, the virtue of saving one’s own soul, while no attempt at social salvation is made. Both Catholics and Protestants he labelled vile heretics, inasmuch as they have turned aside from the social teaching of Christianity. If we are to love our neighbour as ourselves we must as a whole community work for the betterment of our fellows socially, by erecting a form of society more in accord with Christian principles. We must strive to do it here and now, and not sit piously getting ready for the next world. We must not think it religious to despise the body or material welfare. God manifests Himself as matter and spirit, so Religion must not despise economics but rather unite industry and science as Love unites spirit and matter. Eternal Life, of which Christianity makes so much, is not to be sought, argued Saint-Simon, in another world, but here and now in the love and service of our brothers, in the uplift of humanity as a whole.