Dante's poem, and particularly its allegorical qualities, provoked commentary almost from the moment of its completion. Indeed, Dante himself was perhaps its first critic. In a letter he wrote to his patron, Can Grande della Scala, the man to whom he dedicated the Paradise , Dante suggested that his poem should be read on four levels. The first level is the literal one. On this level, the poem is about a physical journey toward God taken by the poet himself. The other three levels are allegorical, abstractly symbolic, and very complex. From the beginning of its public life, commentators have extracted and studied these abstract allegorical meanings of Dante's epic, to dig deeper meanings out of its literal level just as they did with Holy Scripture. As Ricardo Quinones notes in Dante Alighieri, 1979, there were twelve commentaries written on the Divine Comedy from Dante's death in 1321 to...