The work at first came anonymously from the press, and the mystery of its authorship was sedulously maintained in the introductory observations of Naigeon, in consequence of the danger which then attended the issue of Infidel productions, not only in France but throughout Christendom. The book was printed in Amsterdam, at d'Holbach's own expense, by Marc-Michael Rey, a noble printer, to whom the world is greatly indebted for the inestimable aid he rendered the philosophers. But bold as he was, and then living in a country the most free of any in the world, he dared not openly send these Letters from his own press. They were issued in 1768, in two duodecimo volumes, without any publisher's name, and with the imprint of _London_ on the title page, in order to set those persecutors at bay who were prowling for victims, and who sought to burn author, printer, and book at the same pile. The prudence of the author and printer saved _them_ from this fate; but the book had hardly reached France before its sale was forbidden under penalty of fines and imprisonment, and it was condemned by an act of Parliament to be burnt by the public executioner in the streets of Paris, all of which particulars will be narrated in the Biographical Memoir of Baron d'Holbach, which I am now preparing for the press. Of the excellence of the Letters to Eugenia, nothing need here be said. The work speaks for itself, and abounds in that eloquence peculiar to its author, and overflows with kindly sentiments of humanity, benevolence and virtue. Like d'Holbach's other works, it is distinguished by an ardent love of liberty, and an invincible hatred of despotism; by an unanswerable logic, by deep thought, and by profound ideas. The tyrant and the priest are both displayed in their true colors; but while the author shows himself inexorable as fate towards oppressive hierarchies and false ideas, he is tender as an infant to the unfortunate, to those overburdened with unreasonable impositions, to those who need consolation and guidance, and to those searching after truth. Addressed, as the Letters were, to a lady suffering from religious falsehoods and terrors, the object of the writer is set forth in the motto from Lucretius which he placed on the title page, and which may thus be expressed in English:-- "Reason's pure light I seek to give the mind, And from Religion's fetters free mankind." A. C. M.