How much does the historical Buddha matter to the Buddhist traditions?

What are the Four Truths? How do Buddhists understand them?

What was the original Buddhist monkish ideal? What has that ideal evolved into?

What is the connection between Buddhist psychology and Buddhist cosmology?

What is dependent arising? To what extent is it a replacement concept for the self?

What is the Abhidharma? Explain in detail.

What is the Mahayana?

What are the three major Buddhist traditions? What are the distinctions between them?