The Republic is the second longest of Plato's works but likely the greatest of them all. It is a collection of ten books each containing dialogues arranged in certain groups representing some of the most important concepts ancient thinkers ever reached. There are many other writings on how these vital truths should be considered, but none of them encompass the same scope or are as detailed. They remain as relevant today as they did some 2,500 years ago when written.
"I am the wisest man alive, for I know one thing, and that is that I know nothing." Plato
Be sure to look for the companion volume containing Benjamin Jowett's 'Introduction & Analysis of the Republic by Stew Hanley