This is what I have to relate of the life of Plotinos. He had, however, asked me to arrange and revise his works. I promised both him and his friends to work on them. I did not judge it wise to arrange them in confusion chronologically. So I imitated Apollodorus of Athens, and Andronicus the Peripatetician, the former collecting in ten volumes the comedies of Epicharmus, and the latter dividing into treatises the works of Aristotle and Theophrastus, gathering together the writings that referred to the same subject. Likewise, I grouped the fifty-four books of Plotinos into six groups of nine (Enneads), in honor of the perfect numbers six and nine. Into each Ennead I have gathered the books that treat of the same matter, in each case prefixing the most important ones.
The First Ennead contains the writings that treat of Morals. They are:
1. What is an Animal? What is a Man? 53. 2. Of the Virtues, 19. 3. Of Dialectics, 20. 4. Of Happiness, 46. 5. Does Happiness (consist in Duration)? 36. 6. Of Beauty, 1. 7. Of the First Good, and of the Other Goods, 54. 8. Of the Origin of Evils, 51. 9. Of (Reasonable) Suicide, 16.
Such are the topics considered in the First Ennead; which thus contains what relates to morals.
In the Second Ennead are grouped the writings that treat of Physics, of the World, and of all that it contains. They are:
1. (Of the World), 40. 2. Of the (Circular) Motion (of the Heavens), 14. 3. Of the Influence of the Stars, 52. 4. (Of both Matters) (Sensible and Intelligible), 12. 5. Of Potentiality and Actuality, 25. 6. Of Quality (and of Form), 17. 7. Of Mixture, Where there is Total Penetratration, 37. 8. Of Vision. Why do Distant Objects Seem Smaller? 35. 9. (Against Those Who say that the Demiurgic Creator is Evil, as well as The World Itself), Against the Gnostics, 33.
The Third Ennead, which also relates to the world, contains the different speculations referring thereto. Here are its component writings:
1. Of Destiny, 3. 2. Of Providence, the First, 47. 3. Of Providence, the Second, 48. 4. Of the Guardian Spirit who was Allotted to Us, 15. 5. Of Love, 50. 6. Of the Impassibility of Incorporeal Things, 26. 7. Of Eternity of Time, 45. 8. Of Nature, of Contemplation, and of the One, 30. 9. Different Speculations, 13.