Sample-driven music derives as much of its allure from the creative process, which allows artists to turn profits with subtext-drenched stories of obsessive crate-digging, visionary editing, and patchwork collage-making that rewires history in every exposed seam. Such conceptual richness inflates sampledelic currency from hip-hop to dance music, but it doesn't begin to relate the enormous appeal of The Avalanches' Since I Left You. Quite possibly the best sample record ever made, the album comprises close to 1,000 snippets that come together in a psychedelic disco fry-up too woozy to be dance music, but too groove-heavy to be anything else. The Australian band's dirty-handed production sounds most like the warbly film-stock recordings of mid-period Mercury Rev, but the results lean closer to Daft Punk's lo-fi house and the breezy brilliance of Dan "The Automator" Nakamura and Kid Koala. Part of The Avalanches' genius, however, lies in the way it leaves the details on the cutting-room floor. The album-opening title track is a pastiche of weightless shimmer, a lazy day's disco groove dotted with tickling xylophones and sauntering glockenspiels. The blissed-out breeze picks up the guitar line from Madonna's "Holiday" (the only authorized Madonna sample to date) on "Stay Another Season," before blowing into the '60s seaside environs of "Two Hearts In 3/4 Time." Pulling from an impossible array of sources, from jazz and tropicalia to novelty records and sound-effects discs, the band crafts a process-intensive work that can only be heard on its own giddily recombinant terms. The disc occasionally touches down on breakbeat electro ("Flight Tonight") and turntablist hip-hop ("Frontier Psychiatrist"), but more often hovers beyond the reach of anything so concrete. It sounds like a novel written entirely with adjectives, or a suggestive transmission from an overwhelmingly joyful sound world.