On their second album, soulful space cadets André 3000 and Big Boi channel the unexpected success of their debut, and their rising stature as Southern rap ambassadors, into something darker and knottier. P-Funk grooves, dub, and gospel simmer alongside fish, grits, and all that pimpin'. But the boldest innovations on ATLiens happen within the rapping itself, like the dizzying cadences of "Babylon" or the subject of "13th Floor / Growing Old," a piercing meditation on mortality—simultaneously of this world and out of it.