The most accessible "classical" album in the Zappa catalog is, not surprisingly, also the one most recognizably related to his pop styles. In this world, blues filigrees bump up against surprise polkas that stomp off into atonal back alleys. It's rambunctious, but also thoughtfully arranged and sequenced. It helps, of course, that many of the themes were already road-tested on more traditional Zappa albums like 200 Motels. But "Pedro's Dowry," new to his catalog as of this recording -- and revisited by other groups in later years -- is something any Zappa fan ought to spend real time with.