This is sort of like jazz in its own peculiar way, Zappa says during a rap in “Be-Bop Tango,” and he’s right, because Roxy & Elsewhere is about as close to a traditional musical form as the Mothers are ever likely to come. There’s bound to be lots of strangeness — long, spoken raps (preambles), Zappa’s own weird form of humor, post-acid fairy tale lyrics and a lot of just plain wasted vinyl — on any double album from the Mothers. But in between there is actually lots of solid and inventive jazz-rock. When Zappa tries (which is rare) he is one fine guitarist, and the rest of the Mothers could doubtless run rings around anyone else in the jazz-rock field if they ever considered it worth their while. Basically, though, you either love Zappa and the Mothers or you loathe them, and Roxy & Elsewhere is still an album for fans only.