Problematisation about concepts and related notions in Aristotle greatly depends on the particular work or works under consideration. Richard McKirahan’s contribution ‘Concepts and Concept Formation in Aristotle’s Logical Works’ argues that an account of how concepts are formed may be extracted from passages of the Organon, on topics relating to the problem of how we gain knowledge of scientific principles, in combination with Aristotle’s statements on the relations among objects in the world, affections in the soul, and language. Aristotle’s view is pieced together on the basis of the account in Posterior Analytics 2.19, supplemented by the parallel account in Metaph. A.1, as well as Aristotle’s remarks on the utility of dialectic for the sciences in Top. 1.2 and the brief discussions of epagōgē (frequently and controversially rendered by ‘induction’: An. Post. 1.18 and 1.31). The chapter also addresses questions about the nature of perception as conceived in the Organon, the epistemic status of experience, the transition from the awareness of individuals to the grasp of universals, the status of nous, and the relation between universals and concepts.