The Divine Comedy
The greatest long poem in the Western tradition after Homer, and arguably the most architecturally perfect. Hell, Purgatory, and Paradise as a cosmological journey through which Dante maps the entire moral universe of medieval Christianity. The Inferno (with its psychological precision in imagining torments fitted perfectly to sins) has never been equaled as a work of moral imagination. T.S. Eliot put it plainly: "Dante and Shakespeare divide the modern world between them; there is no third."
Everyone finishes Inferno, some finish Purgatorio, and almost nobody finishes Paradiso, where the poetry dissolves into doctrine and light. You will need a footnote for every third tercet of Florentine score-settling, and in English you are reading a shadow of the terza rima anyway. Dante put his personal enemies in Hell and called it cosmology; admire the nerve, budget for the homework.
The case for it and the rest of the canon open with Pro.
