 Given the divergence of expert opinion about even the most basic aspects of Aristotle’s Categories, it is inevitable that an attempt to give a neutral account of the basic positions it contains will be seen as wrong-headed, perhaps drastically so, by some scholars or other. One could attempt to address this problem by commenting on every scholarly debate and opinion, but such a project would fail to bring to life the most striking features of Aristotelian categorialism. In what follows, therefore, I shall take a different route. I first present a natural, though perhaps overly simplified, interpretation of the main structures in Aristotle’s categorial scheme, while pausing en route to note some especially controversial points. I then go on to discuss one important scholarly and philosophical debate about the categories, namely the question of whether there is some systematic procedure by which Aristotle generated his famous list. The debate is of interest in large part because it concerns one of the most fundamental metaphysical topics: what is the correct system of categories? I am not ultimately concerned to present the correct interpretation of Aristotle’s Categories. Rather, I only hope to provide a useful introduction to the content of this endlessly fascinating work.