Symbolism, Imagery, Allegory
Bradley Pearson was employed as an Inspector of Taxes throughout most of his working life, and although the novel doesn't draw a lot of attention to this point, it's possible to see some allegorical connections between Bradley's former day job and his vocation as a writer.
If we think of both tax inspection and writing—or the kind of writing that Bradley undertakes in The Black Prince, anyway—as forms of examining and assessing accounts, and of calling people to account for their words and deeds, those symbolic connections become clearer.
Whether he's probing an individual's finances or attempting to plumb the depths of human consciousness, Bradley Pearson is just as good at inspection as he is at introspection.