Ruth Underwood (born Ruth Komanoff; May 23, 1946) is an American musician best known for playing xylophone, marimba, vibraphone, and other percussion instruments for Frank Zappa and his band The Mothers of Invention. She played for Zappa from 1968 until his death. She married fellow Zappa musician Ian Underwood.
From Wikipedia
Ruth Underwood (née Komanoff; May 23, 1946) is an American musician best known for playing xylophone, marimba, vibraphone, and other percussion instruments for Frank Zappa and his band The Mothers of Invention. She played for Zappa from 1968 until the mid-1970s, and again briefly before Zappa's death in 1993. She married fellow Zappa musician Ian Underwood.