  Spinoza defines the term “attribute” in Definition 4 of Part One of the Ethics thus: “Per attributum intelligo id, quod intellectus de substantia percipit, tanquam ejusdem essentiam constituens.” That is, “By attribute I understand what the intellect perceives of substance as constituting its essence.”[1]  Nonetheless, it is astonishing how little agreement there is among scholars as to some of the most basic features of Spinoza’s theory of attributes. For this reason, this article first considers the important places where Spinoza establishes fundamental characteristics of attributes: such as their definition, their real distinction, and their identification with the substance. It then explains the main issue on which interpretations diverge and signals in broad terms which interpretative avenues have been taken or are conceptually open (without delving too deeply into any one of them). In light of these very different interpretative avenues the article revisits some of the characteristics explained in the first part and considers how they are affected by the different kinds of interpretations. Finally, and perhaps most importantly, given the holistic and systematic nature of Spinoza’s metaphysics and the central role attributes play in it, the article points out how the different interpretative options on one issue bear on others (e.g. the number of attributes and the understanding of 2P7 and its scholium). The different ways of understanding Spinoza’s theory of attributes inevitably give rise to very different conceptions of Spinoza’s metaphysics as a whole.