Although improvisation is critical to what Whitney Balliett famously labeled the “sound of surprise,” the svelte and complex arrangements on this long-obscure masterpiece prove that extemporaneity is not the be-all and end-all of jazz. Extension, recorded in the Pacific Jazz Studios in Hollywood in 1963, does boast fine solos from composer/arranger Fischer on piano and organ, and Jerry Coker on tenor saxophone and clarinet. But the album’s owes its timeless appeal to the colors and textures that Fischer coaxed from an orchestra that included Bud Shank (flute, alto sax), Gary Foster (clarinet, tenor), Don Shelton (clarinet, alto), and drummers Colin Bailey and Larry Bunker doubling on vibes. Fischer labored for months on these fascinating blends of woodwinds, brass (French horns, trombones, tuba), keyboards, bass, and percussion. And while the pleasant opening waltz, “Ornithardy,” only hints at the intrigue that unfolds in the subsequent seven tracks, the depth and subtlety of the impressionist voicings and dynamics grow ever more enthralling over the next 27 minutes, with echoes of Ellington, Stravinsky, and more. The astounding sonic accuracy and richness of this first-time transfer from three- track analog tapes to beautifully packaged CD make the listening experience that much more exquisite.