Porphyry's Launching-Points to the Realm of the Mind An Introduction to the Neoplatonic Philosophy of Plotinus

As the title says it's a launching point into the philosophy of Plotinus. A very short and to the point book which gives bullet points and explanations to the key sections to Plotinus's philosophy. You glean enough to have an idea of what Plotinus had to say and perhaps develop the desire to jump into the Ennead and begin wading your way through it.