In this chapter, the author illuminates the way self-knowledge and theoretical knowledge are intimately related through a close reading of Plato’s most famous image. Instead of concentrating solely on the shadow-like objects of the prisoner’s perception and cognition, the author turns our attention to the psychic changes undergone by the prisoner himself and thus detects a crucial, but heretofore unexamined, emphasis on self-knowledge. The chapter argues that there are four distinct types of self-knowledge at work in the allegory, each of which corresponds to a section of the divided line. The chapter sheds light on the close relation of self-knowledge and knowledge in Plato at the same time as it looks forward – by way of considering Socrates’ insistence that the philosopher return to the cave – to the practical dimensions of self-knowledge.