Various Artists

The Sea and the Bells

Rather than shunning these developments as echoes of one of rock’s more dubious tangents, critics and fans alike have embraced them, declaring guitar rock null and void and heralding “post rock” as a whole new pop vocabulary. All of which raises the question: So who’s pretentious now?

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Into this morass the Rhino label has hurled a real depth charge. The five-CD progressive-rock comp Supernatural Fairy Tales is a fairly exhaustive survey of the era (1967-’76), and it sheds some light on the music of our own era as well.

As Supernatural Fairy Tales makes clear, what starts off as musical adventure can turn to bombast or self-indulgence in a heartbeat. At Tortoise’s last Chicago performance there were a few scary moments when the band’s more upbeat jams recalled those of jazz fusion pioneer Weather Report. And instrumental ensemble Rachel’s recently released a record that embodies many of prog’s worst tendencies.

What remains to be seen is which post rockers will one day be compared to effete windbags like Seventh Wave and Rare Bird and which will measure up to substantive adventurers like Quiet Sun and Van der Graaf Generator. One thing is certain: it doesn’t pay to dismiss your predecessors as irrelevant. For as Supernatural Fairy Tales beautifully illustrates, those who don’t learn their history are destined to repeat it.