by him was the Letters to Eugenia. These were the preludes to more than a quarter of a hundred different productions numbering among them such books as _Good Sense, The System of Nature, Ecce Homo, Priests Unmasked, &c, &c._, all printed anonymously or pseudonymously at his own expense, without a possibility of pecuniary advantage, and with such extraordinary secrecy as to show that he was actuated by no desire of literary fame. It was love of truth alone that impelled d'Holbach to write. Brilliant, profound, eloquent and excellent as were his writings, attracting notice as they did from the civil and religious powers, commented upon as they were by such men as Voltaire and Frederick the Great, admired as they were by that class who felt and combated the evils of tyranny as well as of religion, of kings as well as of priests,--that class who almost drew their life from the books of him and his compeers,--he was never seduced from the rule he originally laid down for his literary conduct. A very few persons he was obliged to trust in order to get his writings printed, and but for that fact Baron d'Holbach would now only be known as a gentleman of great wealth, extensive benevolence, and uncommon liberality, as a man of profound learning and agreeable colloquial powers, as the bountiful friend of men of letters, as the soother of the distressed, as the protector of the miserable, and as the affectionate husband and father. So much of him we should have known; but that he was the author of those books which roused intolerant priests and corrupt magistrates, consistories and parliaments, monarchs and philosophers, the people and their oppressors,--that he was the Archimedes that thus moved the world,--would not have been known had he not employed another philosopher, by the name of Naigeon, to carry his manuscripts to Amsterdam, and to direct their printing by Marc-Michel Rey. It was Naigeon who carried the manuscript of the Letters to Eugenia to Holland, together with a number of others by the same author, which also appeared during the year 1768,--an eventful year in the history of Infidel progress. The _Letters_ were carefully revised by d'Holbach before they were sent to press. All the passages of a purely personal character were omitted, some new matter was incorporated, and some sentences were added purposely to keep the author and the lady he addressed in impenetrable obscurity. To raise the veil from a man of so much worth and genius, as well as to carry out his idea of doing good, is one of the reasons which have led to the present preparation and publication of this book. A. C. M. LETTERS TO EUGENIA LETTER I. Of the Sources of Credulity, and of the Motives which should lead to an examination of religion.