Plato is the philosopher famous for his work "The Republic," a foundational text in Western philosophy. Written around 380 BCE, the work outlines Plato's vision of a just society and explores concepts such as justice, governance, and the role of the philosopher-king. In "The Republic," Plato presents his theory of Forms and the allegory of the cave, highlighting the distinction between the world of appearances and the world of reality. His ideas have profoundly impacted philosophical thought and political theory throughout history.