The Republic by Plato - is a Socratic dialogue, authored by Plato around 375 BCE, concerning justice, the order and character of the just city-state, and the just man. It is Plato's best-known work, and one of the world's most influential works of philosophy and political theory, both intellectually and historically.
In the dialogue, Socrates discusses the meaning of justice and whether the just man is happier than the unjust man with various Athenians and foreigners. He considers the natures of existing regimes and then proposes a series of hypothetical cities in comparison, culminating in Kallipolis, a utopian city-state ruled by a philosopher-king. They also discuss ageing, love, theory of forms, the immortality of the soul, and the role of the philosopher and of poetry in society. The dialogue's setting seems to be the time of the Peloponnesian War.
While visiting the city of Piraeus with Glaucon, Polemarchus tells Socrates to join him for a romp. They eventually end up at Polemarchus' house where Socrates encounters Polemarchus' father Cephalus.
In his first philosophical conversation with the group members, Socrates gets into a conversation with Cephalus. The first real philosophical question posed by Plato in the book is when Socrates asks "is life painful at that age, or what report do you make of it?" when speaking to Cephalus who is older than Socrates.
Cephalus answers by saying that many are unhappy about old age because they miss their youth, but he then says that he has met other men who do not feel this way. Cephalus mentions a story that when he was in the presence of one of these men named Sophocles and he was asked "how do you feel about love, Sophocles are you still capable of it? To which he replied, Hush! if you please: to my great delight I have escaped from it, and feel as if I have escaped from a frantic and savage master." Cephalus states that he feels that Sophocles has spoken wisely and that "unquestionably for old age brings us profound repose and freedom from this and other passions. When the appetites have abated, and their force is diminished, the description of Sophocles is perfectly realized. It is like being delivered from a multitude of furious masters." This seems to set Socrates at ease and the conversations move on to discuss Justice.
Plato is seemingly interested with aging and love and in what affect they will have on him. It is a brief but salient point and the book's first real philosophical discussion.