Because his reputation for antagonistic eccentricity is so strong, it’s easy to overlook the astonishing musical accomplishment of Captain Beefheart’s 1967 debut. Don Van Vliet was still searching for a definitive sound, and from one angle, Safe As Milk separates the constituent parts that would soon fuse for Trout Mask Replica. Fueled by the playing of a 20-year-old guitar whiz named Ry Cooder, the album encompasses garage rock (“Zig Zag Wanderer”), doo-wop (“I’m Glad”), R&B (“Call On Me”) and Dadaist outbursts (“Abba Zaba,” “Dropout Boogie”). Above all, Beefheart and his Magic Band took deep blues as source material and kneaded it into the grotesque and wonderful shapes of “Sure ‘Nuff ‘n’ Yes, I Do,” “Plastic Factory” and “Grown So Ugly,” the last of which is a cover of an obscure song by Louisiana singer Robert Pete Williams. The great “Electricity” comes on like a typhoon, and most predicts the Magic Band’s future sound. Just as essential are the bonus tracks (13 to 19), which show the Magic Band breaking through to totally uncharted forms of mangled, triumphant American soul music.