Clocking in at a mere 27 minutes, this watershed 1964 collection of 12 instrumentals remains one of the most significant progressive-bluegrass records. While the Country Gentlemen were expanding the bluegrass repertoire and mindset (not to mention audience) back East, these youthful Southern California urbanites were displaying a wide-open, free-swinging picking style that signaled a further change in the genre's direction. Flat-picking master Clarence White deserves the lion's share of credit: all of 19 years old, White revolutionized bluegrass guitar with an exciting, blues-drenched, rhythmically unrestrained, tasteful, and cohesive technique. Doc Watson had only recently been "discovered," but Watson's open-string, banjo-derived style, which allowed guitarists to handle speedy fiddle licks, provided the final piece to White's puzzle. White's work on "Nine Pound Hammer," "Billy in the Lowground," and "Sally Goodin" is astonishing, as is his interplay throughout with brother Roland's mandolin. The familiar melodies range from traditional fiddle tunes to old-time folk to Bob Wills. Pickers from Tony Rice to Jerry Garcia acknowledge their debt to Clarence White, a debt they began accruing with this landmark release. --Marc Greilsamer