The Mahabharata
The longest epic in the world: the war at Kurukshetra, the Bhagavad Gita within it, and a civilization's inquiry into dharma.
The Mahabharata is roughly ten times the length of the Iliad and the Odyssey combined, and it says of itself that what is not in it is nowhere. That is close to true. Law, statecraft, cosmology, philosophy and the Bhagavad Gita all sit inside a family quarrel over a throne.
What makes it strange as an epic is its moral vision. Nobody is clean. The heroes gamble away their wife, kill by deceit, and are told so. The villain keeps his word. The text knows it is doing this, and returns repeatedly to the question of what dharma requires when every available choice violates it.
Its composition ran across centuries, and the critical edition assembled at Poona under V. S. Sukthankar tried to work back toward an earliest recoverable text.
These pages set out the story, the structure, and what the epic is actually arguing about.