The Republic by Plato, written around 380 BC, is the best known work of Plato as well as one of the most widely read & influential works of philosophy ever written. It is written as a dialogue – specifically, a Socratic dialogue. These particular works are written to solve philosophical problems & concerns by way of two or more characters conversing with each other, with Socrates often appearing as the main subject.
The Republic discusses many of the philosophies of Plato, including his theory of forms, the immortality of the soul, the ideal of the philosopher-king, and more. It is written as 10 books, each of which features Socrates engaging in philosophical debate & Socratic dialogue with other characters. The Republic has been commented on by scores of philosophers, writers, and rulers – each of whom seem to respect it for its place in antiquity (at the least), even if they might disagree with Plato on the substance.