The treatise of Origen _Against Celsus_ is, of all his works, the most interesting to the modern reader. It is a defence of Christianity in opposition to a Greek philosopher named Celsus, who had attacked it in a work entitled Ἀληθὴς Λόγος, that is, _The True Word_, or _The True Discourse_. Of this work we know nothing, except from the quotations contained in the answer given to it by Origen. Nor has anything very certain been ascertained respecting its author. According to Origen, he was a follower of Epicurus, but others have regarded him as a Platonist. If we may judge of the work by those specimens of it preserved in the reply of Origen, it was little better than a compound of sophistry and slander. But there is reason to be grateful for it, as having called forth the admirable answer of Origen. This work was written in the old age of our author, and is composed with great care; while it abounds with proofs of the widest erudition. It is also perfectly orthodox; and, as Bishop Bull has remarked, it is only fair that we should judge from a work written with the view of being considered by the world at large, and with the most elaborate care, as to the mature and finally accepted views of the author. The best edition of Origen’s works is that superintended by Charles and Charles Vincent de la Rue, Paris 1783, 4 vols. fol., which is reprinted by Migne. There is also an edition in 25 volumes, based upon that of De la Rue, but without the Latin translation, by Lommatzsch, Berlin 1831-1848. The _De Principiis_ has been separately edited by Redepenning, Leipzig 1836. Spencer edited the _Contra Celsum_, Cambridge 1677. PROLOGUE OF RUFINUS TO THE DE PRINCIPIIS.