Last year, I read Five Dialogues by Plato and reviewed them on this site. This year I've revisited Plato's Republic, which I read in college. In this most famous of Plato's dialogues, Socrates, who is always the main character in Plato's works, makes a proposal to some friends: he can demonstrate that a virtuous man is always happier than an unvirtuous man. Some of his interlocutors scoff, saying that virtuous men may be happier because society esteems them, but if they were able to be unvirtuous without anybody knowing, they would do so in an instant.
To demonstrate his point, Socrates builds a perfectly virtuous city, with the idea that by examining a larger entity (a city), it may be easier to spot virtue and its effects and then transfer those lessons to a smaller entity (a man). This conceptual building of the city takes up the bulk of the book. By the end, Socrates has described a city guarded by a well-educated warrior class, and led by a philosopher-king. He then compares this city, which he demonstrates to be the happiest of all cities, with four other types of cities in order of their happiness: first, honor-loving cities ruled by warriors; second, money-loving cities ruled by merchants; third, democracies ruled by the people; and finally the unhappiest of cities, despotisms ruled by a tyrant.
Then, he compares each of the type of cities to different types of men: philosophers who love knowledge and truth correspond to his perfect city; followed by honor-loving warriors, money-loving merchants; undisciplined democrats, and tyrants.
Thus, he demonstrates to his friends' satisfaction (if not quite the modern reader's) that each succeeding type of city is less and less happy. Correspondingly, he also shows that philosophers, who with their love of knowledge and truth are the most just of men, are also the happiest, and each succeeding type of man is less and less happy.
What I found interesting is how he believes the guardians and the philosopher-king in his perfect city should be educated. He thinks as children they should receive training in poetry and music, elementary mathematics, and physical training. Those who exhibit the right temperaments will move on as teenagers to three years of vigorous physical training followed by ten years of mathematics (!), at which point they'll be ready to be guardians. Those guardians who might advance to leadership roles will then receive five years of "dialectic" training (i.e. making and weighing arguments), followed by ten years of studying what we would call political science. Only then, in their mid-forties, would they be ready to lead a city.
If this sounds simplistic, it is not, for Socrates also anticipates all sorts of counterarguments and negates them. One counterargument I found impressive was his explanation of why an unjust man may appear to others to be successful and admirable. He compares such a man to a runner who gets a fast start in a race, and appears to spectators to be far in the lead. But as time goes on and the lead runner tires and falls behind, so the unjust man finds his way is not so easy as creditors, friends, and neighbors discover his true nature and gradually stop interacting with him.
Like the Five Dialogues, this book is pretty easy to read, at least on a line by line basis. Socrates' language is straight-forward and conversational, as indeed, it is supposed to be a conversation among he and his friends. The simplicity of the language frees your attention for the consideration of his sophisticated arguments.
I don't think I would recommend this to somebody looking for light reading (although as I say above, it is not actually that hard to read), but for those willing to think about ethics, virtue, and how we order our society, this is arguably the most basic text in Western literature on those topics. Actually, the book has much the feel of a late-night bull session in a dorm room, so for the right kind of person, I think the Republic might be not only thought-provoking, but even fun to read.