Plotinus (205-269 AD) led the philosophical movement of Neoplatonism, which reinterpreted Plato's thought later in antiquity and went on to become a dominant force in the history of ideas. Emilsson's in-depth study of Plotinus' central doctrine of Intellect caters for the increasing interest in Plotinus with philosophical clarity and rigor.
Worth 5 stars for the discussion of double activity alone. If you want to understand Plotinus' views on emanation, this is far and away the best place to go. I'd almost go so far as to say this book is the key to it all! Almost. In particular, the sheer clarity of the writing is a huge boon to Plotinus scholarship, which is too often just a tad less rigorous than one would like. While Plotinus' thought is by no means intuitive or commonsensical, this work shows that it does not suffer from a lack of coherence or profound metaphysical insight.
I read this as part of my thesis that applied persistence theory to Plotinus' metaphysics.
The book goes into serious depth and is well-referenced. Don't let the title fool you: although the focus is the concept of Intellect, the other hypostases (The One/Good and Soul) are also explained in quite a bit of detail.