Purgatory O/P

From the Introduction: Considered as an artistic whole, which of course it is, the Comedy is something greater than the sum of its parts and each of the parts is essential to its meaning. Yet such was the genius of Dante that each part has its own special significance and its own unity. Granting that no one of the three main divisions could be spared if the poem is to say all the author meant it to, the point may fairly be made that the Purgatory could be spared least of all.