This volume reconstructs Aristotle’s view of the cognition of essences and engages with the current debate on it. Its main thesis is that the source of some current interpretive tensions lies with Aristotle himself, who holds both that knowledge of essence is gained a posteriori and that it is irreducible to perceptual experience. The aim of the book is to show, by contrasting Aristotle’s philosophy of science and his philosophical psychology, that his position is coherent. While this strategy has often been neglected in more recent studies for methodological reasons, this study aims to show how fruitful it is.