This chapter addresses an inevitable question: How are later books of the Republic, and specifically Book 4, related to Book 1? It contends that justice as conceived in Book 1 is “external,” concerned with how one entity regards and treats another, and so is at odds with the novel definition of justice in Book 4, according to which it is “internal,” a matter of what happens within a single entity, whether a city or a soul. It is argued that in Book 4, Socrates, having been tasked with persuading Glaucon and Adeimantus that there is profit in being just, identifies a reward for being just, namely, the harmonious internal state of city and soul. Although he briefly calls this healthy and therefore desirable condition “justice,” he more frequently and aptly identifies it as “moderation.” This chapter makes the case that it is the account of justice found in Book 1 that more closely reflects Socrates’ (or Plato’s) understanding of it.