Dirty finds Sonic Youth revisiting the territory the band mapped out on Sister -- merging the propulsive structures of rock (both punk and otherwise) with the gorgeous chaos of their approach to the electric guitar -- and it shows how much better they'd gotten at it in the past five years, from the curiously beautiful "Wish Fulfillment" and "Theresa's Sound World" to the brutal "Drunken Butterfly" and "Purr." Dirty was also Sonic Youth's most overtly political album, railing against the abuses of the Reagan/Bush era on "Youth Against Fascism," "Swimsuit Issue," and "Chapel Hill," a surprising move from a band so often in love with cryptic irony. Heard today, Dirty doesn't sound like a masterpiece (like Daydream Nation) or a gesture toward the mainstream audience (like Goo) -- it just sounds like a damn good rock album, and on those terms it ranks with Sonic Youth's best work.