The material on this album was originally was intended to be part of a four-record set called Läther, prepared for release in 1977. Then Frank Zappa got into a disagreement with his record company, Warner Bros., and Läther was split up into several different releases as part of a contractual agreement. The results were dumped on the market in 1978 and 1979, while Zappa moved on to his own record label. Sleep Dirt consists of miscellaneous tracks recorded between 1974 and 1976, including "Flambay," "Spider of Destiny," and "Time Is Money," songs that wre apparently part of an unissued Zappa musical/rock opera from 1972 called Hunchentoot. They are sung by soprano Thana Harris. It's impossible to say what the entire work would have been like, but this album is little more than musical fragments.
AllMusic Review by William Ruhlmann