Socrates, and Plato, and Aristotle?

I wanted to delve into Rhetoric but then was slapped in the face by the three said historians. I know a scarce amount about them, but I was curious which types of literature I should search for, if I wanted to read up on rhetoric. Also how many books did each person write, would the average person comprehend what he would be reading and what was each one of these men known for?