Masters of Greek Thought: Plato, Socrates, and Aristotle, a 36-lecture course, either audio or video, taught by Professor Robert C. Bartlett, Boston College, provides a detailed analysis of the golden age of Athenian philosophy and the philosophical consequences that occurred when Socrates—followed first by his student Plato and then by Plato's own student Aristotle—permanently altered our approach to the most important questions humanity can pose.

Course description:

For more than two millennia, philosophers have grappled with life’s most profound issues. It is easy to forget, however, that these “eternal” questions are not eternal at all; rather, they once had to be asked for the first time. It was the Athenian citizen and philosopher Socrates who first asked these questions in the 5th century B.C. “Socrates,” notes award-winning Professor Robert C. Bartlett, “was responsible for a fundamentally new way of philosophizing”: trying to understand the world by reason.

Online:
The Great Courses