"I have been but little in," said Ninian hastily...

Reading a SciF/Fantasy book review, I came across this passage.

It’s a literary trope that does exist outside the sf genre, but it’s much harder to find, and in my mind at least is rarely as viscerally satisfying.

Is it just me, or do others feel this betrays the reviewer's astounding lack of familiarity with much of mainstream literature? It seems as if just this sort of self-realisation is a terrifically common part of modern fiction, from Charles Dickens to JD Salinger to Jhumpa Lahiri.

OK, literary bods, I can't remember. Who was the 19th century American writer who did most of his work while whiling away dull hours in a government job in Washington? It's killing me that (a) I can't remember and (b) I can't figure out how to Google/Wikipedia it.