Since the untimely death of Frank Zappa in 1993, fans of his music have patiently awaited the release of additional unissued tracks from his huge personal archives in his home studio.

Imaginary Diseases features a series of live recordings from a 1972 tour by Zappa's so-called Petite Wazoo band, a ten-piece group that was full of potential but never sufficiently documented on commercial albums during his lifetime.

The miniature "Oddients" has an avant-garde flavor with a bit of encourage audience participation in the vocal chants.

"Rollo" was often performed as the finale to the suite of songs heard on the first side of the album Apostrophe, though this version omits the vocals heard on some bootleg issues.

"Farther Oblivion," a song recorded as a part of that suite, is very different in this conception, including snippets that would later be incorporated into the magnum opus "Gregerry Peccary" and songs like "Bebop Tango" and "Cucamonga," also showcasing Tom Malone's effective tuba.

"Been to Kansas City in A Minor" is an extended blues workout with a blistering solo by the leader.

"D.C.

Boogie" initially has a Middle Eastern flavor, though it gradually shifts into a driving boogie, contrasting Zappa's invigorating fuzz tone with Tony Duran's rocking slide guitar.

"Imaginary Diseases" features another blistering Zappa solo, bracketed on each side by a peppy showcase of brass and reeds.

Zappa has the only solo in the cooking jam "Montreal." The sound on these 1972 concert recordings is at times a little rawer than typical Zappa live albums of the era.

But it seems likely that he worked on them briefly before turning his focus to various other projects, leaving them for Zappa Records "vaultmeister" Joe Travers to uncover and prepare for release.