Symbolism, Imagery, Allegory
Pilate’s geography book has been with her since she was a little girl and remains a constant source of intrigue, reminding her of all the places she has been to, and all the places she has yet to see. At one point, Guitar tells Milkman that he feels his whole life is geography.
The Southside community is acutely aware of geography both on grand and infinitesimal scales. For one thing, Southside is the southern portion of the city by Lake Superior (which we assume is Detroit, Michigan, though we are never explicitly told this). The fact that the black community is concentrated in the southern portion of a northern city recalls the once divided country, separated between North and South, Yankees and Confederates, those free and those locked in slavery.
We are also reminded of the Great Migration which took place after the Civil War and which saw many freed slaves move to northern cities. Our protagonist, however, follows the reverse migration, beginning in the North and ending in South, where his ancestors once dwelled. All characters that inhabit Song of Solomon seem acutely aware of where they are in relation to other places.