Republic

The Republic is one of the most important dialogues of the ancient Greek philosopher Plato. It is renowned for its detailed expositions of political and ethical justice. Unlike his early or Socratic dialogues, the Republic reflects the positive views of Plato himself. The middle dialogues are literary as well as philosophical masterpieces.
In The Republic, Plato sets out to explain what justice is and why doing what is right is to everyone's best benefit. Socrates suggests that this investigation can be furthered by looking at justice "writ large" in a perfect society. The ideal state, according to Plato, consists of three social classes: the rulers, the guardians (or warriors), and the producers (e.g., farmers and craftsmen).
The three components of a person's soul—reason, spirit, and appetite—are social classes. While appetite has the customary low preferences for food, drink, and sex, the spirit is focused on honor and competitive principles. A situation similar to political justice is justice in the individual, often known as ethical justice. Each component of the soul is in full operation, and there is psychic harmony.