Recorded in 1968 and released in 1969, The Marble Index is a unique experience that was shockingly avant-garde for its time. The singer/songwriter conventions of her solo debut album, Chelsea Girl, were jettisoned for John Cale's avant-classical arrangements. Her harmonium was matched by his electric viola, mouth organ, and a variety of treated keyboards and guitars. Just as her work with The Velvet Underground expanded the definition of rock 'n' roll, The Marble Index expands the definition of the singer/songwriter. Nico's own songwriting is presented for the first time, and it's as eerie as her singing voice. "Lawns of Dawn" is a web of sound where nothing is stable and everything is forever changing. "No One Is There" aches with a loneliness that Cale's swaths of strings can do little to assuage. These are brooding numbers that inspired the next generation of doom and goth rockers, few of whom truly understood the eloquence of these unusual tunes. "Roses in the Snow" and the a capella "Nibelungen" were bonus tracks added when the album was reissued in the '90s, flawlessly extending the record's mood.