With respect to the works of Porphyry which are translated in this volume, the first, which is _On Abstinence from Animal Food_, is a treatise not only replete with great erudition, but is remarkable for the purity of life which it inculcates, and the sanctity of conception with which it abounds. At the same time it must be remembered, that it was written solely, as Porphyry himself informs us, with a view to the man who wishes in the present life to liberate himself as much as possible from the fetters of the corporeal nature, in order that he may elevate his intellectual eye to the contemplation of _truly-existing being_ (το οντως ον,) and may establish himself in deity as in his paternal port[4]. But such a one, as he beautifully observes, must divest himself of every thing of a mortal nature which he has assumed, must withdraw himself from sense and imagination, and the irrationality with which they are attended, and from an adhering affection and passion towards them; and must enter the stadium naked and unclothed, striving for the most glorious of all prizes, the Olympia of the soul[5]. Hence, says he, “my discourse is not directed to those who are occupied in sordid mechanical arts, nor to those who are engaged in athletic exercises; neither to soldiers nor sailors, nor rhetoricians, _nor to those who lead an active life_[6]; but I write to the man who considers what he is, whence he came, and whither he ought to tend, and who, in what pertains to nutriment and other necessary concerns, is different from those who propose to themselves other kinds of life; _for to none but such as these do I direct my discourse_[7].” This treatise, also, is highly valuable for the historical information which it contains, independently of the philosophical beauties with which it abounds. The _Explanation of the Homeric Cave of the Nymphs_, which follows next, is not only remarkable for the great erudition which it displays, but also for containing some profound arcana of the mythology and symbolical theology of the Greeks. And the third treatise, which is denominated _Auxiliaries to the Perception of Intelligibles_, may be considered as an excellent introduction to the works of Plotinus in general, from which a great part of it is extracted, and in particular, to the following books of that most sublime genius, viz. On the Virtues[8]; On the Impassivity of Incorporeal Natures[9]; and On Truly-Existing Being, in which it is demonstrated that such being is every where one and the same whole[10]. This Porphyrian treatise, also, is admirably calculated to afford assistance to the student of the Theological Elements of Proclus, a work never to be sufficiently praised for the scientific accuracy, profundity of conception, and luminous development of the most important dogmas, which it displays.