by Plato
from Prismatext
Recognized one of the most influential books on Western philosophy and political theory, The Republic is a dialogue centered on the concept of justice, specifically as it pertains to both the state and the individual.
Plato, through the voice of Socrates, is ultimately concerned with the question of justice, its definition, and whether or not it can affect happiness. Plato also introduces his theory of universals through his famous Allegory of the Cave, and in doing so presents the framework of the ideal world.