Classic noir: A subgenre of mystery that includes authors such as Dashiell Hammett, James Cain, Raymond Chandler and Cornell Woolrich. Anything that also qualifies as "hard-boiled" will work for this square.
“It's a dangerous business, Frodo, going out your door. You step onto the road, and if you don't keep your feet, there's no knowing where you might be swept off to.”
-- J.R.R. Tolkien, The Lord of the Rings