The role and precise significance of Intelligible Matter in the philosophy of Plotinus has been neglected or dismissed with many questions unanswered. In view of the fact that, unless this role can be properly understood, the whole doctrine of the procession of the Second Hypostasis must remain mysterious, this paper is intended to shed light on two important aspects of that Hypostasis: the nature of Intelligible Matter itself and the relation of that Matter to the Forms.