I enjoy Plato's Republic for its Socratic dialogue format and its devotion to the topic of justice.
Western philosophy is a very important part of history
It is indeed. And Plato's thought serves as the foundation to nearly all of Western philosophy. I suppose you could credit Aristotle for that too.
Aristotle made impacts on nearly every facet of human knowledge, ethics, and aesthetics.
He did. Reading the Nicomachean Ethics, Poetics, Politics, Organon, etc. will give one a good background on these subjects.
Yes have you extensively studied these subjects?
Somewhat. I'm in the process of reading Aristotle's Nicomachean Ethics, and I've finished Plato's Republic, but I haven't read much beyond that.
The Nicomachean text influenced the study of ethics for centuries!
It absolutely did. And it spawned quite literally all of Western ethical thought. 
The office research ethics manages the use of research in regard to ethics