The undertaking is indeed no less novel than arduous, since the author of it has to tread in paths which have been untrodden for upwards of a thousand years, and to bring to light truths which for that extended period have been concealed in Greek. Let not the reader, therefore, be surprised at the solitariness of the paths through which I shall attempt to conduct him, or at the novelty of the objects which will present themselves in the journey: for perhaps he may fortunately recollect that he has traveled the same road before, that the scenes were once familiar to him, and that the country through which he is passing is his native land. At, least, if his sight should be dim, and his memory oblivious, (for the objects which he will meet with can only be seen by the most piercing eyes,) and his absence from them has been lamentably long, let him implore the power of wisdom, From mortal mists to purify his eyes, That God and man he may distinctly see. Let us also, imploring the assistance of the same illuminating power, begin the solitary journey. Of all the dogmas of Plato, that concerning the first principle of things as far transcends in sublimity the doctrine of other philosophers of a different sect, on this subject, as this supreme cause of all transcends other causes.