Ivor Darreg (May 5, 1917 – February 12, 1994) was an American composer and leading proponent of microtonal or "xenharmonic" music.
At that point he took on the name "Ivor," which means "man with bow" (from his cello-playing talents) and "Drareg" (the retrograde of "Gerard"), which he soon changed to "Darreg".
Darreg lived for much of his adult life in or near Los Angeles, California, then spent his final nine years in San Diego.
Ivor sported a long beard to cover the fact that due to both an illness and confrontation from a violent break-in to his home in the 1950s, he had lost his teeth.
Darreg's informal network of microtonal musicians writing letters to each other later morphed into the more formal Xenharmonic Alliance.